Early light period?

Paris
Okay I just have a quick question, this last month I've been on steroids for an allergic reaction & I was wondering if it would cause my pills to be unaffective. I'm about 3 days & having light cramps & some blood. should I be worried? I've heard of girls having spotting & what not while they're pregnant but I just wanna know about how much that is. Thank you for the help.