Okay I need some advice!!!

Im 19 and I live with my boyfriend, we moved to Colorado in February 2011, when we were kicked out of my brothers house on valentines day ( long story ) anywho, we left with us, some clothes and a ferret.

we got to colorado manage to get an apartment and we actually made out pretty good.

Now my problem is...

I havent had my period for maybe a year and 8 - 9 months before I met my bf, but last month I got my period on the 9th - 13th, but we've been having unprotected sex, and he hasnt pulled out either since August.

so last time he did it was Sept 14th. (Around the 19th - 20th I took a test and it was negative but we also had unprotected sex on Sept 4th, but back to the story!) lately i've been really nauseous, my back hurts so much, im so tired ( I gotta leave to work in alittle and all I wanna do is climb back into bed, shoot me ), my boobs are way bigger, but they dont' hurt. and I have a history of getting the worlds worst cramps but lately they been mild or just a tingle. & im emotional.

i'm just so confused, I wanna be pregnant, is it just wishful thinking?