Making the switch to formula

Long story short, we have had a pretty fussy baby since about 2 weeks old. We confirmed he has reflux and I have cut out all dairy since mid November. He is still pretty fussy, but doesn’t spit up nearly as much as he did before. My question is, should I try formula for a few days to see if it’s my breast I’ll causing the fussiness? I would pump to keep my milk supply going. I just feel so bad for him. You can see that he wants to be happy. He will be smiling one minute and then just melt down. My pediatrician said if I wanted to, to try 10 days of similar alimentum and see how he seems. Just looking for advice or similar situations. My first son was a nursing champ and a happy little guy so I’m just at a loss.