Gastric ache ..!

Yesterday was went to First Station again, i reached there at 10.30pm. I was order a glass of Lemon Coke, but i just drink 1/4 only, then i was left already. It is because suddenly my gastric felt so pain, i can't help it anymore, thats why i left earlier. Actually before i go out i was already feeling not very well to my gastric, i thought i will be okey if i go out to walk walk, but it doesnt help anything to me.