Could I be pregnant?

I know this sounds crazy, but I am just going to put it out there. I am 34 years old. For the last few months, I have just not been feeling right. Mostly exhaustion, gas and stomach pains. I have even have had some breast tenderness and swelling. My stomach just feels off majority of the time. I have taken numerous home pregnancy tests that have all been negative and I had a blood test 2 weeks ago that was also negative. If I was pregnant, I would be about 6 months. I swear that I am feeling movement in my lower abdomen, along with random twitching that I have never felt in that area before. I used to have regular periods, but those have changed over the last few months and are now incredibly light and only a couple days. I have read that some women do continue to bleed even when pregnant. I am overweight, but I have managed to loose a little over 50 pounds in the last eight months without even trying. Again, I have read that obese women will loose weight during pregnancy as the baby is feeding off of their nutrients. Is it possible that HCG may not ever be detected and that I could still be coming up negative this far along in pregnancy or am I just reading way too into things and letting my mind get the best of me?