Irregular period all of a sudden

Hey guys. Im a college student and I am hoping someone can give me some advice. I’ve been on the pill for about 5 years now. About a year ago I switched brands (due to insurance not covering my old brand) and I’ve been on Taytulla since. I’ve always had regular periods starting on a Saturday and then ending about Tuesday/Wednesday and my periods have always been light/medium flow, sometimes with cramps and sometimes without. I’ve never missed pills and if I’ve taken them late it was by an hour. This month, my period wasn’t like usual. I had brown discharge/light bleeding for 4 days and then it stopped. It hardly filled up a regular tampon. Is this normal? I’ve never experienced this before and Its been stressing me out because I’m not trying to have kids (I’m also in the middle of finals week). I’ve read sudden intense exercise and diet change can affect your period on the pill and I just started lifting intense heavy weights this month. Please help a girl out 😅