My stomach is very upset. in pain no fever. no covid symptoms. may be stress from work. sleep deprive?

Antacids: Usually any antacid or even otc famotidine, cimetidine, prilosec or nexium. Can use short term, a few days to a week. If you don't relief see a provider.

GI upset: Doubt COVID 19 or sleep. Symptoms of sleep deprivation can include irritability, feeling tired, poor concentration, decreased memory, changes in appetite, poorer ability to handle stress, lack of comprehension with social interactions.

Need to examine: It is not feasible to provide a meaningful opinion without taking additional history, physical examination and may be some tests. It would be prudent to see your doctor and discuss if you may be depressed. Counter-intuitive as it may seem, exercise may help. Start with low intensity exercise such as walking and gradually increase the intensity as tolerated. Wish you good health!