Ok here goes so back in August I had sex with this guy and then a week later I got what I thought was my period, but it only lasted a day and a half and was very lite so I didn't pay it much attention. I became concerned when I got my period right on schedule, but this one too was very lite and only lasted two days which is very unusual because usually my flow is very heavy and lasts four to five days. I had also begun to notice a persistent ache in my lower back, being constantly tired and hungry and also darker nipples with what appears to be little bumps on them. Taking all of this into consideration I decided to take a pregnancy test well actually a few, but they were all negative. I decided to go to the doctor just to make sure and their urine test and blood test were both negative so I pretty much forgot about it. However four months have gone by and I've started to notice what looks like a baby bump. Also I can see my veins under my skin on my breasts, legs, and stomach, which is very unusual because I could never really see them before. It also seems like my heart is beating way harder than it usually does and the last couple of times I checked my resting heart rate it was between 95 and 105. Are these things normal or could I really be pregnant despite all of the negatives?

It happens often. Women test too early and get negative results, and then assume they're not pregnant.

When was the last time you tested? When you tested did you use first morning urine? Did the doctor ever do a blood test? If so, when?