I Feel Nauseous Usually In Am. I'm 80 Have Had

I feel nauseous usually in am. I'm 80 have had blood work which is fine. I don't have it every day but it started about 6/28/2015. I've also had a stress test which was fine.I take Atenalol, Diazide, Omeprozole, levothyroxin, and simvastatin. I don't have it every day. I could go 5 to 8 days at a time feeling fine. Any ideas?