How soon will I know?

[LoveFever]

This might get confusing, because I don't really know how to explain it...
I was supposed to have had my period last week, but didn't, even though I hadn't had sex or done anything sexual in a while.
But the other day I went over to this guy's house and we had unprotected sex and I still haven't had my period.
I was supposed to have gotten it BEFORE I had sex with him, so I really have no clue what's going on.
It was just three days ago that I had sex with him, so I know it's too early to tell, but I was just wondering when I will be able to take a test and get an accurate result?
Thanks!

[escape_thereal_world]

Two weeks (14days) after unprotected sex should give you an accurate result. Test again in two days to a week if you want to be certain.

Your period might not have come from stress, change in diet, sleep routine, or just your routine. Our bodies are very sensitive to any change.

[Aletheia*]

Two weeks from when you had unprotected sex should give you an accurate result. Remember, lot's of factors can cause your period to be late. Anything from stress to changes in diet or a new exercise regime could cause your period to be late or not come at all. So, in about two weeks or less than that, take a test to ease your mind. I doubt you're pregnant from before, since you said it was a while since you last engaged in sexual activity and you should have had symptoms from that.