Will Plan B One Step work with this?

So I had unprotected sec on Oct 31. I know I was stupid. He came but he pulled out in time. I took Plan B One Step 7-8 hours later. I'm just freaking out because I think I was ovulating but I'm not sure. It's now Nov 10 and still no period. I have been getting lower period like back cramps and white discharge. My question is, will Plan B work during ovulation? I've read some saying yes it does work and some saying no. I've been freaking out for an entire week. My periods come at random times. I guess you can say I'm irregular when it comes to my cycle. Statistics and % of effectiveness will be HIGHLY appreciated.