So I've been exclusively breastfeeding since my baby was born. He is 3 months old now and I went out drinking last night... I had a couple of bottles already pumped to prepare.. I continued to pump and dump this morning but ran out of "good" breast milk and didn't feel comfortable yet because I drank way too much ... So I fed him formula and the first bottle he was fine with but after the next feeding he vomited up the entire bottle... I thought maybe he just had eaten too fast so I didn't think anything of it but then he slept through the next feeding ( which has not happend yet)  at his next feeding six hours later I fed him another formula bottle and he projectile vomited all over the place... So I gave him a bath and wait a while to see if he's acting like he's still hungry and decide to feed him from my boob because I felt like I had pumped and dumped enough... And he vomited up all of my boob milk!... What do I do?? ...is it just because I gave him formula after only feeding him breast milk? Or is he getting sick?