implantation bleeding vs irregular period

Okay, so I am on the pill. And when sexually active my partner and I use condoms. If we don't he pulls out very very early. But for a week or so now I have been bleeding on and off. I'll bleed for a day or two then it'll stop. Couple days later I'll only see blood when wiping etc. I'm sure it's just my body adjusting to my pills since I'm new to them, but I want to be sure. We're only in high school and are in no place to have a kid. Please please help!!