Helpppp!!!!!!!

I don't know what to do. I had a d&c; July 12 and I have had two normal periods since. My last period was august 16-19. I was due last Wednesday the 13 of September. I have took 3 test and they have all came out negative. I just feel pregnant, I just have a feeling. I am just scared that I go to the doctor and they say there test is negative too or something is wrong????? I don't know what to do. My boyfriend things that I am just over thinking it and that my period is just messing up, but I just have a gut feeling. What should I do?