please let me be paranoid…

I thnk i might be pregnant… Im 17 and have been going out with my current bf for 6 months. about a month ago i had sex for the first time in my life. We became closer and everything is wonderful. unfortunastely i have the feeling i might be pregnant… (and just to clarify i dont want to be pregnant…) About 2 weeks ago (right after we did it) i started to bleed, my periods have always been out of whack, going from a day long to 2 weeks, and could be as far away as 6 months or a month. it usually happens when im stressed. i figured because of the new experiences i was having, it was just reacting. but 2 days ago i felt naucious and have ben lying in bed ever since. i feel like i have a stomach ache (almost like normal cramps) and i have a fever(if that means anyhting), also i cant really eat anything wihtout feeling naucious, but i feel hungry all the time. I dont have any other symptoms but it is freaking me out. We always use condoms and they havnt broken or anyhting. My mom doesnt know i am sxually active but about a month ago (b4 we started having sex) i told her i wanted to go on the pill to see if i could regualte my periods, she agreed and i have been waiting for my period to come so i could take them. She has already said in many discussions if i ever became pregnant i better not be in her house or i would be kicked out. I cant stand this feeling and in my small town it is impossible to but a test without a parent. I have nevr been to a gynecologist… which i know is bad, but it scares me…. Im really worried… could i be pregnant or am i just freaking out? help?