I'm having trouble breast feeding my son who is 11 days old. I didn't have any problems until yesterday. He's been able to latch on and suck since he was an hour old. My milk supply came in slowly so we were supplementing with formula. I was still able to breast feed him what I could. As of yesterday he still latches on and takes a couple of sucks and then he latches off and gets really upset. I don't know if he just doesn't like the taste of breast milk anymore or...