The 2wws were always the worst part especially day 13! There is a website called twoweekwait.com where people post their pregnancy symptoms and dates of pregnancy tests which I recommend if you want to obsess (but don't if you want to keep your mind off it). Most pregnant people on that site seem to have tested positive by day 13 but not all of them. Try not to be too disappointed if AF comes. I had 3 IUIs with Clomid and all BFN. We are now in the middle of our first IVF cycle (just had the retrieval yesterday). I know that my most disappointing cycle was probably my first IUI with Clomid
Congratulations on your first IUI ! :-)) Did you do the Ovidrel injection to stimulate ovulation?? If so, BELIEVE ME, it is pure hormones and it will really trick you into thinking you might be PG by imitating many early pregnancy symptoms. I had my first IUI mid October and in the TWW (2 week wait) I had many symptoms that were very unusual for me (not like period symptoms) and I was sure I was PG....only to sadly find out my period showed up just like clockwork! :-(( I am on to Try #2 now, middle of this month and I am determined I WILL NOT analyze every little cramp, breast soreness, etc. I was driving myself crazy!
If you didn't do the injection, it's possible that your breast soreness is just an common pre-period symptom. I'm not trying to discourage you, just trying to make you be cautious....that darn negative test is a bummer!! I know, I've been there! :-))
Take another test in a couple of days and see what it says.....hopefully it will turn positive for you!!! I have heard that it takes some people a little longer for the HCG hormone (pregnancy hormone) to be detectable in your urine....so maybe and prayerfully you are one of those people!! :-))
BEST OF LUCK TO YOU........AND ~~****** BABY DUST TO ALL !!! ******~~