Need advice when to test

[AHP84]

Well, I'm going to officially join the "could I be pregnant" posting club. Actually, the question is more geared towards when I should test, because I know there could be a chance I'm pregnant.
Here's my issue.
I have the Mirena IUD and as far as I know, it's placed properly. I make sure to check the strings once a month as advised. I had it placed in early April this year at my 6 week post-natal exam. Since then, I have not had a period that I'm aware of, but only twice have noticed some extremely light spotting. The last occurance of spotting was about two weeks ago and lasted for a day. I know this is a common thing to expect from the Mirena, as well as the fact that I'm exclusively breastfeeding. So I really don't know if that was my period or if it was just some random spotting. Or if it could have been implantation bleeding (but I never had implantation bleeding in my last two pregnancies).
Moving on to this week.
On Sunday, I was feeling really out of it; just very tired and a little moody. By Monday, I was beginning to feel sick with what seems to be a sinus infection, and my moodiness since Monday has been overwhelming. I feel depressed, overly fatigued, zoned out, and my patience for anything and everything is non-existant.
Also on Monday, my milk supply increased significantly by nearly two ounces per pumping session (I pump three times a day). Then by Tuesday, it plummeted to about an ounce and a half less than what I normally get per pump session, and has been holding steady at that rate since then. My milk supply increases and decreases from time to time, but not that drastically in a one day timeframe. Nothing in my diet has changed and I am not on any medication to affect the supply, so I don't know what to think of it.
By Tuesday, what seems to be my allergies and oncoming sinus infection began to peak. By Wednesday (yesterday), the flu-like feeling began to set in by the afternoon, along with nausea, which I never get with a true sinus infection. This morning, I swear I have morning sickness because I am nauseated, I threw up a little after taking my vitamins, and my head feels like it's swimming. I've also been yawning a lot since Tuesday.
So this is why I'm concerned about pregnancy: for my last two pregnancies, I got allergies/sinus infections with flu-like symptoms, nausea, and excessive yawning the week before I tested and got postive results. Also with my last two pregnancies, I got sore breasts, but now that I'm breastfeeding, my breasts are always tender, so I have that potential symptom too. However, with my last two pregnancies, I never got menstrual or abdominal cramping that early, and I do not have it this time, either. Just the tell-tale signs that I've gotten the last two times.
So my question is, when should I test? It was easy to determine when to test the last two times because my period was due but didn't come. This time, I don't have a clue where I am in my cycle.
I know the severe risks of becoming pregnant and having an IUD, so I know I need to test. I just don't know when because I have no idea if I'd be testing too early and get a negative result. Like I said, in my last two pregnancies, I got all these symptoms a week before I tested, which would have put me at about 8-12 DPO those times. Both times I tested before, I know I was at least 14 DPO.
I have a dollar store test at home that is not expired, but I don't know how reliable it is. Should I use it to test tomorrow morning with FMU or should I wait a few more days, or should I get a Clear Blue or First Response and test tomorrow morning?
I just hope I'm only getting sick and having mood swings from the Mirena. I can't afford another baby right now. :-(

[Michele, Katy, TX]

Hi AH.  I actually MIGHT be pregnant as well but I am only 5 dpo, so I won't test for another week and a half or so depending on if AF shows up.  I chart my BBT along w/ other fertility signs so I know exactly when to expect AF.  Anyway, because of this and because I am still exclusively BFing, I have been doing some research on BFing and pregnancy.  I know you can get pregnant while nursing but it is highly unlikely within the first 6 months of your baby's life if you are exclusively BFing.  I will try to copy and paste the site here but if it stars it out, I will PM you.  Very interesting reading and it has informed me and will help me to inform others....Take care.

http://www.kathydettwyler.org/detfert.html

[AHP84]

Well, I tested this morning and it is negative. That doesn't make me feel much better though; not just yet, anyway. Plus I'm still feeling physically off.
Keeping my fingers crossed that I'm just fighting off some weird virus or something. I know my chances of pregnancy are almost non-existant with the Mirena, but there still always is that chance. My OB was really making that a point on the day I had it placed, explaining that they're almost always ver effective, but the previous week, she had just diagnosed an ectopic pregnancy due to a Mirena.
I guess I'll test one more time on Sunday or Monday if I'm not feeling better by then. Maybe I'm just a little paranoid on top of being sick. I know the mind can play tricks on you too.

[AHP84]

Thank you.
I don't think it's mastitis. I don't have a fever, and my breasts aren't agonizingly painful, just tender, which is an everyday thing because of the breastfeeding. Nothing is anything out of the ordinary with how they feel as far as tenderness, due to the breastfeeding. If I wasn't breastfeeding and they were tender like they are now, then I'd be even more concerned, but as it is for that particular symptom, I just don't know.
I wouldn't be so concerned over what is hopefully just a sinus infection, but I've had plenty of sinus infections before (just got over one about three weeks ago), and nausea is never a symptom--except for when I'm pregnant. Ugh.
I'll test tomorrow morning with the dollar store test I already have at home, and if I get a negative, then I'll buy a higher quality test tomorrow afternoon to test on Saturday morning.

[Limonada]

I don't have any experience with IUDs (sorry), but I'd say that you should test tomorrow with FMU and, if possible, one of the tests where positives can show with a lower level of HCG.  Even if you get a negative result, I'd say to retest, particularly if your symptoms persist.  

Sorry if this is a dumb question since you didn't mention any breast symptoms, but could you possibly have mastitis?  It wouldn't explain the sinus symptoms, but I know that I had flu like symptoms when I had it, felt AWFUL!  Just a thought :-)

Good luck and keep us posted!!!!