Had some slight red spotting now having cramps

I’m 30 weeks and 1 day pregnant, i’ve been having on and off spotting for 2 weeks now. I don’t get the red spotting every day maybe 2-3 times a week and its very random when i get it. Anyways, i was just having some spots on TP and now i’m having cramps in my pelvic area. Kind of heavy feeling when i walk.. I’ve called about the spotting they don’t say much. Any advice on what i should do?