breastfeeding help!!

my son was and I were amazing at breastfeeding, from day 1 he knew what to do and I had multiple nurses and health professionals tell me I looked like a natural born breastfeeding pro. he breastfed perfectly for 2 months but all of a sudden the last few days he will barely stay on the breast for a minute without starting to fuss and cry! I've checked in his mouth and there are no sores or signs of thrash. it's not my milk because he will take a bottle of pumped milk no problem. he has a strong suck and is fine with a soother. literally nothing has changed except he is pretty much refusing to stay on my breast now. his environment is the same, his position is the same, he acts like his normal self until I try to feed him. he wants to eat but something is bothering him and I can't figure it out. I've called a breastfeeding helpline and they couldn't figure out what it could be so they told me to make an appointment with a doctor asap and said they could also get me an appointment with a lactation consultant. but in the meantime I want to know if anyone has any suggestions.