12 week old Baby feeding less??

An

My baby was consuming about 125-150ml of formula every 3-4 hours and as of yesterday he has only been taking in about 75ml and 125ml if I’m lucky every 2.5-3 hours. Why could this be happening? I’m a FTM. Is it possible he’s going through a growth spurt and will go back to normal soon? The few days before this he was consuming more formula than normal.