Started feeling sick with cramps and nausea followed by aches and then vomiting, my stool today was grey and bad smell. i am taking strong pain killers and antacids, is stool colour a concern.this began 2 days ago after eating fish in a restaurant?

Usually stool color is mostly related to diet. But, having pain with nausea/vomiting indicates that something is wrong. Did anyone else eat what you ate? Are they sick as well? If so, food poisoning is a possibility. If others ate the same food and they are not sick, then it is less likely. If these symptoms continue, you need to be seen by a doctor-perhaps urgent care or ER. Good luck!