Diabetes and stomach problems

I have type 2 diabetes but even before I was aware of it, I would have problems with nausea. Is diabetes and problems with one's stomach related to higher A1C numbers? My last A1c was 7.0, it came up from my previous 6.2. I have had a hard time the past month and a half with nausea a lot after eating, and my stomach hurting before and after eating. It has gotten to the point that I do not want to even eat due to fullness, the nausea and the pain that I am having. I also belch a lot. My doctor ordered an ultrasound but it was fine. He is wanting to get my A1C number down before he looks into my stomach problem some more but I feel like I am getting worse. I am now wondering if a liquid diet would be better for me. I do not feel like doing anything but sleeping a lot to get away from the symptoms. Should I press the doctor more to find out what is wrong with me and could it not be even diabetic related??