Not doing well with cows milk?

So my girl had to be on nutramigen because literally every other formula was terrible for her (super fussy, constipated, wouldn’t sleep). Now that’s she’s one they had us wean to cows milk ... and I am worried it’s not sitting well with her. She’s been EXTREMELY fussy, like totally not her normal self. She’s fighting all naps and getting deliriously tired. She’s having temper tantrums. She’s not eating nearly as many solids as she previously was.

We aren’t sure if this is coincidental timing following her one year vaccinations, or if we can attribute this to milk. Curious if any of you have experienced this or if any of you are doing cows milk alternatives?