I need help!!!

Okay so my period always comes when eve tells maybe 1 day late but that’s it. My partner and I had sex on the 23 of Jan and I’m now 4 days late. At first my breast was sore but not anymore and I’ve been cramping a lil. So today I woke up and found out that I was bleeding. My cramps are strong but my flow is light idk what to do, I don’t know if that’s my period or is blood from pregnancy. ( Im waiting one week to make a pregnancy test.)

I really need to know what’s going on. Does somebody had/has the same problem?