Miscarriage? Help

Hi I don’t know what’s going on I took pregnancy test all week got positive with vvfl very faint lines. I already set up my first appointment and last night I started cramping really bad and I started bleeding like a period I’m using a pad and it blood like a period I don’t know if this is normal if I had a miscarriage or ir it’s my period that’s late and my test were wrong all along or if it’s normal I’m suppose to be 3 weeks pregnant. Has this happened to anyone before?