Pregnant or not confused?

My boyfriend and i have been having unprotected sex. The last period I had was in August and it is now november and i still havent had a period. I have had implantation bleeding in place of my period in August and then nothing after that for the last 2-3 months. I took a home pregnancy test and a blood test and they both came back negative. I have severe nausea, cramping as if i was gonna get my period, break outs, extreme fatigue to the point where i feel like i never get enough sleep lately, weird cravings, and nausea during and after intercourse, no vomiting, and secretions coming out of my breast, that never happened since the last time i was pregnant about 3 and a half years ago. I sometimes get a headache and other people says that i have mood swings. I wonder if the test are wrong because i feel pregnant; by the way we dont use any type of birth control what so ever. Could I be pregnant and its laying doormat until I have enough HcG hormones to read a positive. HELP