NEED ADVICE!!

Hey mommas, so 3 days ago I had cramping in my lower back and stomach, exactly like period cramps. I’m 7 weeks postpartum . I went to the bathroom and I bled through my underwear and almost my pajamas. The following next two days I had no blood and it’s just a little brown when I wipe. Is my period just slowly getting back into routine or could it be something else ?? I really could use some advice!!

Also my postpartum bleeding stopped at 3 weeks, and I’ve been sexually active since 4