6 months post Nissen surgery

I am 6 months post Nissen Fundoplication surgery and having a lot of problems after eating. Within 30-60 minutes I am dry heaving and trying to throw up. I have not been able to throw up since the surgery so this dry heaving is very painful. It is almost like I am trying to throw up all of my insides. It really doesn't matter what I eat it just does not seem to settle with me. It comes on me very quickly and without a heads up. This can be very embarrassing if I am around other people and have to cover my mouth and find a bathroom or hiding place outside to dry heave. I am not sure if this is normal, what to do about it? Could it be I am eating to much at one sitting? I don't know if this has anything to do with the procedure or I have other issues going on?

Does anyone know what kind of exercises should be avoided post Nissen fundoplication and hiatal hernia repair surgery? I’m 6 months out now. Finally back to most foods. I no longer eat foods that expand in my stomach like pasta or bread for example. The feeling of overeating can be extremely painful. I would however like to do more exercises other than walking or bicycling if it’s possible?