How are things going now?
We had a mare who had previously mothered perfectly fine reject a foal a couple-few years ago. She had a very difficult dilivery and required lengthy vet attention including an epidural which was a long process to place (mare was a bit fat, etc.). I think we had two factors working against us. We interupted the bonding time, and the mare was in pain. We tried for 5 days with restraining the mare so the foal could nurse, and yes, I mean every 1.5 hours around the clock, and finally gave up. We hand raised him and he grew up fine but it takes a lot of time and feedings very, very frequently at first.
As a routine from the start, we always dose our mares with liquid banamine (1cc per 100# of body weight) following delivery. I don't know that they all "need" it. I'm sure many would muscle through any pain or discomfort, but I wouldn't want to if I were them. I'd want something to help, so all our girls get dosed with bananine. I've read conflicting details whether or not to wait until the placenta passes, and since ours normally do this quickly, we usually do wait.
Just wanted to include this to help whoever it might help, and also was concered about your baby and wanting to be sure that nursing is happening frequently enough? They just have to eat so frequently the first couple-few weeks.
Good luck!