Vasectomy-- chances of pregnancy afterwards?

I'm seeing this new guy who had a vasectomy quite a while ago, we have a lot of sex and just wondering if anyone on here has ever gotten pregnant from a guy who has had that done?

I've heard stories about it being a one-in-a-million chance but possible.

My period is due in 10 days and today I'm having light pink discharge, not normal for me.

We're both clear of STDs.

EDIT: I've also had some random and brief cramps that were fairly sharp, only happened a couple times over the last few days.