We have been through this as well SG. It lasted a few days, the only way I could get him to feed was to sit in a dark room with no noise at all, but sometimes he would still refuse, would feed ok when he was half asleep though. He still plays around sometimes and has very quick feeds, but i think he is just more efficient at getting the milk now. I think this is just a stage most babies go through and it should pass soon. Maybe cut down on the formula if you can, he has probably realised it is easier to get the milk form the bottle...babies can be lazy sods, LOL.