And hun, you're not going to get in any trouble. This man raped you, pretty much by definition, and yes, he will go away for a long time. That's THE most important thing right now... well, besides the fact that you need to get yourself to a doctor, check for STDs, get that baby healthy and checked out, and talk to them about options. You need to get this shit straightened out hun, this is bad news. It'll be okay, but you definatly need to be completly honest with both your boyfriend, and your parents.
Your boyfriend, if he is in any way a decent human being, will forgive a poor young girl like you. You did not cheat on him or anything of the sort, this man raped you, and he is so screwed for that.
Good luck hun. We're all here for you,
PM me if you need anything..
-Melissa-