early miscarriage?

so my period was supposed to start today. I've been getting the cramps and mood swings like I normally do before my period comes, but today I noticed that my period blood isn't normal red blood like usual. Instead my discharge has blood mixed in and it's a light brown instead of normal white. I'm still having cramps and have been feeling really upset today. I had sex twice in the past week and haven't been taking my birth control at the exact same time every night. I wondered if it could be a miscarriage but I don't know anything about that kinda stuff