I Have 3/5 Allergies To Shellfish, Fish, Omegas And Also

I have 3/5 allergies to shellfish, fish, omegas and also peanut butter. Am taking a generic form of nexium and wonder if I could take benedryl instead. I tried eating cod the other night and sometime later experienced stomach upset/pain and pain in shoulder. I took benedryl and it took the symptoms away while the nexium generic didn't.