You are an adult. Live your life and tell your parents that it is possible to knock someone up during the day as well as overnight, and that you know how condoms work.

Your mother's threat is insane.

NEITHER of you did anything wrong, other than talking before you got physical.

You had the conversation about what you were feeling, which was legitimate.. and she shared what she was thinking, which is also legitimate. No one did anything "wrong" - it's just how you both handle the situation going forward.

Give her some space, there was a lot of whiplash reading that couple of paragraphs, and she's likely feeling the same.. Even if she didn't want a relationship you went from friends/flirting/lovers/maybe dating/love/friends...

that's.. a complicated series of emotional changes, and not that there is anything wrong with it, but it's just been a few days, give her some space.. in a little bit, a week or two, send something neutral - the kind of thing you would have talked about prior to the flirting and hookup... You might get a better response then, or you might not, but... it's not time to worry about it until then.