17, had unprotected with boyfriend lastnight...?

I realize it's a possibility I could be pregnant, although I am hoping (and I am sure he is too) that I'm NOT because neither of us are financially set, although he does have a job-but it's only part time...and we both still live at our parents houses. We've been dating for over a year and 8 months, we usually use condoms, but lastnight-well, without givig a bunch of details that are too personal about exactly what happened-simply put, we went without the condom(i know, it was stupid and using the pullout method is just as stupid, especially since i dont think he puled out in time) and i've been off the pill for quite a while now. health reasons. anyway, im wondering how soon symptoms of pregnancy can show up? i've looked i up on the web, but gotten all sorts of answers-im looking for something like medical fact please or your best guess at least. i also have a pretty good idea abut what the symptoms are, but i wonder if i've missed some early ones. also, how affective is the morning after pill? could i go to the pharmacy and get it without paying money for it or does it cost something? how much? help please.