Similac Alimentum Formula questions!!

Sh

So my son is 12 weeks old and has been on similac alimentum since about 2wks old. He spits up a lot, which the doctors say is normal but it seems kind of excessive. It’s not just after feeding a it’s like several times in an hour. Well the last couple days he’s been crying when trying to eat and also been throwing up. This has happened at least once every month since he started on it. I was wondering if anyone had issues like this with this formula? Was there an increase in spit up? I know this formula is supposed to prevent that but it just seems excessive.