I threw up for the first time since surgery last night

I had some tuna fish last night (chopped in the blender, of course). I had eaten some the night before with no problems, although it did give me a heavy feeling in my chest. Last night, I ate it, and got the heavy feeling in my chest and some bad hiccups/burps. I would get them in the past if I don't drink while eating, so figured it would be a problem after surgery because of not being able to eat and drink at the same time. I'm not sure if I'm just not ready to eat tuna yet, if I ate too much, or ate too fast. The hiccup burps got so bad that I took a couple sips of water hoping to make them go away, even though I knew I wasn't supposed to. It didn't help. A couple minutes later, I started getting a nauseous feeling, mouth started watering, etc, and I knew what was coming. So, I walked to the bathroom and vomited. I felt so much better afterwards. I guess I need to be more careful about what/how much/how fast I eat.