Woke up feeling fine. ate a little and drank some fluids. 30 minutes later started feeling really fatigue an slight nausea and hot all over.

Fatigue nausea: May be vasovagal,dehydration, may be GERD/ gastritis with or without H pylori a stomach bacteria May be pregnancy check HCG, would also check thyroid and consider checking gallbladder. UTI can cause unusual symptoms- especially as one gets older- so check urine and check throat for strep. rarely i have seen non standard presentations. if fever may be infection f/u w/ doc