Pains after 5 weeks

Kris
Hey mummies, last couple of days ive been gwttigg really bad back pains and stomach/diaphragm cramps. My little one is 5 weeks old and my afterpains etc haf stopped. 
Cant think of anything ive done to pull something and im limited in pain relief as im breastfeeding. Cant get a dr appointment for another week so wondering if anyone has had anything similar or can offer relief advice.  Currently using heat. 
Thwacks x