nausea when eating fruit

I've had pretty regular nausea since January with some minimal pain. The nausea was so severe at times that I would prefer to not eat for a few days than take the chance at eating and vomiting. I lost about 10 lbs. due to this. The doctors diagnosed gallstones. So I had my gallbladder removed which was full of stones and one stone was lodged in the bile duct. I also had some sort of infection. My pain is gone now but I noticed today that I drank a fruit drink, with only fruits and vitamin C in it, & within 20 minutes I was so sick to my stomach I could hardly stand. This was the case prior to my gallbladder being removed also. This leads me to believe that my nausea is caused by something other than my gallstones. Ever heard of such a thing? What might I try to suggest to my doctors or research on my own for my own home treatments, other than the obvious, "Stop eating fruit!"?