Might be pregnant, but really not sure

[cnicdae]

I am 20 days late for my period. My last AF started Feb 6, 2009.  The average length of my cycles are 30 days.  I have taken 4 HPT and they came out negative.  A blood test at 1.5 weeks late came back negative as well.  Is it possible I might still be pregnant even thought tests said otherwise?  I am tired, feel bloated, tender breasts (to the touch).  My first 2 pregnancies were each different.  My first did not appear on HPT, but a blood test.  My 2nd showed on an HPT when I was about a month along.  

[cnicdae]

I am so confused. Is it possible to be pregnant after having negative HPT?  It is now April 6, 09 and I still haven't had a period (last one started 2/6/09).  My boobs are really sore and I've been getting this weird gassy bloating going on for the last week or so.  I don't want to take another HPT because they are expensive (last one was taken March 20 and it was negative) The only blood test I've had was when I was 2.5 weeks late.  
I am getting mixed answers from people.  Some women say they were pregnant but tests showed negative until they were 4 months along! Some say that because the tests are still negative, then I'm not pregnant.  I don't know what to think.  When I saw my doc at 2.5 weeks late they said to come back again if I still thought I was pregnant and they'd do another test.  I don't know if I'm wasting my time, but I made an appointment for the doc this Thursday.  I wish I knew for sure!  Has anyone else been in similar situations?  If so, what was the outcome?

[cnicdae]

Thanks for your input.  It's nice to hear that I'm not totally crazy for still thinking I might be.  The few people I've talked to about this think that I'm obsessing over it, that I got a negative test and should move on.  But it's hard!  I'd love to have a 3rd baby, especially now that my two are getting so big! : )

[jessbbg]

it's definitely possible----and i think it's probably been long enough now to retest.  I'd start with another urine test tomorrow morning, and depending on the results, go ahead and schedule another blood test for next week.  

I had a friend that didn't test positive at all with either of her pregnancies (they say she likely has a variant form of hcg or something), and another that never tests positive til she's a few months along.

I, on the other hand, turn those pink lines purple like right out of the gate.  I tested positive at 8dpo, a full 7 days before AF was due.