4 days late with my period. one faint positive hpt, two negative. having lots of symptoms. ?

I took one hpt two days ago and it was a faint positive. the next morning i took another hpt (same brand: Walgreen's Early Result Preg. Test) and it was negative. then went to doctor's office today and they did a urine test that was also negative. I definitely had unprotected sex multiple times during 5-6 fertile days this past April. I am now 4 days late on my period. I am bloated, tired, having dizzy spells, heavy breasts, and many other symptoms like indigestion etc. Also tonight I noticed while getting into the shower that the veins going from my pelvic region to the middle of my abdomen are VERY visible. dont know if that is a pregnancy symptom or not but it was kind of unsettling how visible they were. If I were pregnant i would only be like 2-2.5 weeks along. Am I taking the tests too early? Did I have a chemical miscarriage? I still FEEL pregnant even with the neg. results (maybe that's delusional). Is there any chance that I am pregnant? anyone whose undergone a similar situation I would appreciate your input. Thanks