Teething

Hunter has been teething for over a week. He is working on getting his two front teeth which will give him four teeth total!! He has been extremely cranky and needy. I only enjoy it because my baby will sit still for a little while and wants to snuggle with mommy.. It seems to be very painful for the little guy and he has not been eating much, has diarrhea, and a low grade fever. I am now unsure if the diarrhea is coming from the teething or the formula. It is horrible because his little bottom is getting red. Let me know if anyone has any suggestions. I was thinking on starting regular milk a little early instead of switching formula's. Any suggestions??