I've been reading your post, and I know exactly how it feels to feel this way I also lost my virginity at 15, and believe me I freaked out about the same issue (thankfully I wasn't pregnant).. and now when I think about it, as much as I thought I was mature at that age and ready to be having sex... I wasn't. But you live and you learn, and obviously I can't take back my decisions... but I can tell you, just to be careful.. prepare yourself for the worst every single time you have sex, condoms are not 100% protection, and sometimes.. even the pill isn't. (.. of course when taken properly they are... but we're human's and we're forgetful, and we often forget) .. back to my point, just try to relax for the time being... you can't make your period any sooner, and like you said.. you have alot of stress in your life now... so maybe just to put yourself at ease... try a pregnancy test.. hope this helps.
Take care, best of luck... and sorry about your parents
I've also been through that all... but I was much younger then you.