Formula allergy?

Co

Talk to me about milk allergy/intolerance in your babes??.. our two month old has been on similac sensitive for about 5weeks. Initially did well but in the last two weeks started getting really fussy, her spit up has increased but as soon as she spits up she wants to eat again, coughs and some gag/choking. Dr started us on liquid omeprazole thinking it was reflux but now Im wondering about an intolerance or allergy given on the reflux med we aren’t seeing a big improvement. Already ruled our pyloric stenosis and tried zantac as well. She tends to start her day ok and then get worse as the day goes on. What symptoms did your little show with formula issues or anyone else have thoughts?