Weird Spotting (???)

Guys, I'm kind of freaking out. So me and my boyfriend have sex every once in a while, and I haven't missed my period once in the time we've been together. However, I missed it last month and I've been off and on spotting/bleeding for the past few weeks since I've missed it. I have no idea what's going on. I need adivce, help, something! It also usually acts up even more so after we've done something (i.e. sex, fingering me), meaning I'll bleed even more and then it'll kind of stop. This has never happen before, by the way. I'm helplessly confused.