Explain Plan B a little more please?

Adriana
I was ovulating and had u protected sex, he ejaculated inside of me as well... i took plan b 6 hours later when the store opened. It's been 4 days I do not have a period yet. I've been dizzy, nauseous, having sore breast, a little fatigue and crazy mood swings. 
Can somebody help me understand what could possibly be going on? I want to think I took Plan B during the right time as soon as I possibly could... but I was also ovulating that day.