nausea, hot flashes/cold flashes, dizziness, ect? headache lower back pain?!

i have had this lower back pain on and off for a week or so, i've been nauseous for 2 weeks, i've been dizzy for a month, i've just started getting a slight headache, and i just got a really big hot flash that just like took over me. i was just sitting there eating, and i got so hot, then cold..am i pregnant? my boobs hurt to, and my period is suppose to come in like, 2-3 days.. please help, i'm getting concerned, cause i've been feeling like crap for a full month and a half..

and i've been having unprotective sex for almost 8 months, and he's been ..you know, doing his thing inside of me, and we do it probably 2 times in a day, and or every 4 days..