Baby eating too much

I am feeding my baby on demand but lately he has been wanting to eat constantly. He’s almost 7 weeks and would go anywhere from 4-6 oz every 2 hours or sometimes even less than two hours in between. We were feeding in demand until couple days ago he threw up one time and threw up again the next day. He hasn’t threw up again since but we were told to not give him so much milk. We tried giving him a pacifier in between but he wouldn’t take it so he would cry till we give him more milk. He also spit ups quite often and I think it’s wbvause of how much he’s eating. Anyone have any tips for us? 😩