Could I be pregnant ?

My last period was on January 8 and I missed my period for February. My period this month was supposed to start on the 7th and now am a week late. In total I am 37 days late and my cycles are fairly regular and are usually 29 days. I have been having unprotected sex since January 22 but have been using withdrawal (pull out method). In February I had very light pink spotting only when I wiped for two days and had backaches and small cramps, and also had a cold and fever. Now my back still hurts, I have cramps here and there, sometimes I am lightheaded and usually am out of breath and am nauseous but never end up throwing up. I am tired all day and just want to sleep and I have never been like this. Also my breasts are darker and bigger and I seem to be growing a belly, and it looks like i have that dark line under belly button that pregnant women have. My bf told me I look different and that my vagina feels different (bigger/swollen) . All the tests I have taken are negative, but want to believe I can still be pregnant. Did anyone experience something similar ?