Hi Sorry you are feeling so bad.
I was on Prilosec and they switched me to Nexium because it quit helping my issues. I am now on Nexium 20 mg started exactly two weeks ago today and I have not really noticed any difference maybe I need I higher dose or maybe it just takes longer to work. Not all meds work the same for everyone. I have a GI appt on Monday to hopfully schedule a scope (swallowing issues) I will ask about upping my dose to 40 mg. I know its expensive and even having pretty decent insurance I am paying a dollar a pill.
Hope you find relief soon
PS Welcome to the board and the wonderful world of GERD