I feel severely vomitish/nauseous daily (mostly morning and randomly throughout the day). it is not acidity or overeating. I am diabetic but all other blood-work was fine. What else could be the reason? Is it serious? Thanks

Diabetic gastropares. This is a common nerve injury in diabetes in which the movement of food through your digestive system is slowed causing increased fullness and nausea. If your diabetes is well controlled, there are medications which can help the gastroparesis.
Nausea. A common problem in diabetes is very slow emptying of the stomach(gastropareses) which may be causing your symptoms. A gastroenterologist is best qualified to evaluate,advise and treat you for this symptom,however.