It is such a shame that many GPs know very little about bfing. My own GP is brilliant and is very supportive of bfing but admits that he knows very little about it as it's not covered in any detail in their training. It's only GPs who are interested and study it as an extra, or attend ABA seminars for Health Professionals, that know much about it.

I'm sorry that your GP wasn't more supportive, but it's great that you know you are doing a fantastic job. Feeding every 2 -3 hrs is totally normal and exactly what human babies are designed to do. Formula is based on cows' milk and mother cows leave their calves for hours to go and graze, so their milk is designed to sit in their tummies for longer (and their tummies are designed differently to cater for this also). Human baby tummies are tiny and the milk is designed to be easily digested for baby to feed frequently. You and your baby are doing exactly what you are meant to do!

Don't doubt yourself hun. You are doing a great job.

ETA- I forgot to answer your question about the crack. I don't know the answer, but I suggest you call the ABA helpline and ask them. They should be able help - 1800 mum2mum - you don't have to be a member.