Period is so off...

I’m freaking out a little...i started bleeding one Wednesday and my cramps were absolutely killer, which is normal for me. But the bleeding the entire first two days was mostly brown/old blood and the third day i had normal red blood but it was only medium flow really but usually my entire period is super heavy....my cramps were unbearable like normal but I’m freaking out because i know you can still bleed like a period if you’re pregnant and I’m super paranoid. I’m on the pill, have been for almost a year and take it perfectly, and my bf and I always use condoms but I’m still freaked out! I’ve NEVER had a light period. It’s not light like spotting but just light. Someone please help!