Pregnant or Pill?

6 "periods" since I last had sex in February. I'm on the pill but still feel like I could be pregnant. I have taken 8 hpts that were all negative and I had a urine sample sent to the lab to check for hcg levels- came back negative. I had an ultrasound (pelvic)I would have been about 7 weeks if I was pregnant  when I went to the doctors to get my report she said everything looked fine and didn't mention that I could be pregnant.
Could I still be pregnant and it has been overlooked? No negative or mean comments please. I'm generally worried and have had symptoms for weeks (17 weeks) 
It feels like I have period pain every single day even when I'm not on my period, my boobs are sore throughout the month but that stops when I get my period.