Take responsibility for not following the rules. Then don't do it again, and you won't have to worry about it.
Let it be a lesson to you - if you grow up breaking the rules and getting away with it without consequence, you will end up in prison one day wondering why the hell society isn't as forgiving as mom.
I think prison is a little harsh to say the least. I don't think sleeping with your boyfriend dictates a possible prison sentence someday.
Young love is a powerful thing. You didn't say how old you were.If you are 17 or under, shame on your mother for letting him stay the first few times in the first place.
Secondly,It's like giving you candy one day and taking it away the next...not too bright on your mother's part.
I would play it cool for a while until your mother gets over it. Don't argue with her or she will probably get more pissed off.
Shame on you for being ageist
HUH???
Meet your boyfriend some place other than home and let him fuck your brains out, get knocked up then go home and tell your mom you don't know how it happened.
How old are you ??