Recently since stopping medication for post covid bronchitis, i am shakey, gnawing in my stomach, nauseous and anxious. what could be going on?

Monitor breathing and temperature, drink fluids and eat a healthy diet including protein sources. Diabetes screening may be indicated. If you have vomiting, fever,pain, please see acute care. Please follow up with your physician.

Among many other possibilities a degree of relative adrenal insufficiency or steroid withdrawal would be possible providing you had a course of steroids. Your (prescribing) doc will be your best reference at this point.