Discharge ?

Okay so, I’ve been on the pill for about 3-4 months and I’ve skipped my last 3 periods and I recently started having sex so my question is, I keep having a brownish red discharge. Could this be because I’m skipping my pill or something to do with now becoming sexually active? I have slightly bleed twice after having sex but been fine every other time but I’m noticing this a few day after. Any help would be much appreciated ❤️