Having back pain, mild cramping, I had a period 2 weeks ago one day of heavy bleeding and 4 days of spotting. Really bad migraine, rumbling tummy 24/?

Multiples. Things not likely to be interrelated. Probably should be checked for pid.
Pregnancy. Several possibilities, but one big one is pregnancy, which often causes strange periods, brings on or aggravates migraines and changes in appetite. Other signs would be tiredness, nausea when your stomach is empty, tender breasts. Test yourself!