Running out of feeding options..

Please help any advice I’ll take it! My daughter has a severe milk protein allergy, we’ve tried Similac sensitive, Alimentum, now on elecare, and just switched to puramino. She STILL has the worst tummy issues and her dr pretty much said we just have to wait it out. It kills me seeing her in pain idk what to do?? Ive tried everything I can think of from gas drops to gripe water to probiotics, etc. anyone else go through something similar? I can’t just sit back and watch her suffer everyday...I thought for sure switching her formula would help.