I have hurting deep in stomach, a nauseous feeling. just started 3 days ago i do take an acid plocker. ?

I've never had stomach problems. Im 53 years old. Last saturday we went out to eat. That night my stomach didn't feel right. That night and into the next day I had a empty feeling deep in my stomach. It was between a hurting feeling and a nauseous feeling. It wakes me up at night. This mourning I took a drink of poweraid and felt a brief pain a few seconds later. What's going on