Am I pregnant? Please help.

[NS1590]

Hi, I'm 17 years old and my period is 39 days late, I'm on day 68 of my cycle(first day of last period was nov.16) I've taken 3 urine pregnancy tests, and got a blood test done at my doctors, all were negative. I usually have regular periods, and I've been having some pregnancy symptoms, such as nausea,fatigue,headaches,cramps, tender breasts,darker nipples,white discharge,apatite change,bloating,back pain and sometimes constipation. Also as you should know , my boyfriend and I started having unprotected sex over a month ago, and he does *** inside me, every time. I feel pregnant, just don't understand the BFN's :( please help. I do want to be pregnant.