Yesterday i woke up with a terrible burning sensation in my stomach. today its very tender and i feel extremely lethargic. any idea of what it is?

GBD VS acute PUD: This scenario most likely is a toss up between, Acute Peptic Ulcer disease vs Acute GBD, Needs further history to pin the Dx. Othere D/D may need R/O Pancreatitis, Bowel obstruction Patient needs further w/u ASAP, trial of PPI. Blood work, US Abdomen. possible Upper Endoscopy needs to be considered if Xrays and blood work does not shed a light!!