Plan B Questions. HELP!!!!

So I took Plan B on the 22nd of March because we had suspected that the condom had failed because it had slipped off while I was on top of him. In that position there was no way anything could have gotten inside of me, but my boyfriend knew I wouldn't take any chances.
I heard Plan B is supposed to delay your period. For how long?
When you took plan b, did you experience any symptoms similar to pregnancy such as abdominal pain, nausea or frequent urinattion?
With all the responsibility I've taken, there is a minimal chance I could be pregnant. I'm still very scared. HELP!!!!