Hi For Over A Year I've Been Waking Up At

Hi for over a year I've been waking up at 3 am or so with severe belching. Lots of trapped air and it takes me till a bout or 5 am sometimes before I'm comfortable enough to go back to sleep. then I'm up at 7 am for work. I was prescribed Nexium and it hasn't helped so I stopped taking it after a year. The belching is still there and sometimes when I awake in the mornings too. please can you rcommend something for me to help this problem? I 'm happy to suggest it to my GP if it's a prescription medicine.