Day 5 of alimentum change and very gassy

Hello my son is on day 5 of switching to alimentum RTF from gentle ease due to blood in his stools. He has been extremely gassy too to the point he is struggling to drink his bottles. Poor thing draws his legs up and all. He did great days 1 and 2 but He was very gassy to the point of uncomfortableness drinking on day 3 and after giving him gas drops and gripe water day 4 was good. I forgot to give him gripe water in a few bottles and back to drawing his legs and crying passing gas. I wanted to know did the gas eventually settle down for your little one? Did you have to switch to something else? He is pooping and sleeping great. Just the severe gas issue. We did an abrupt change no slow transition. Thank you for responding back.