Brown discharge not placebo pill week

I’ve been on the pill for almost a year and it’s been almost pretty regular expect for a couple times when my period starts a couple days before the placebo pill. I’m not supposed to start the placebo pill till next Tuesday. And I just checked and had a little bit of light brown in my underwear. Any ideas what this could be. I’m on the pill, always use a condom, and he even pulls out with the condom on too. I make sure to be extra safe.