I too had the sleeve and a hernia repair. I had to get daily IV fluids for about 3 weeks. I'm better now at 6 weeks and can get in about 50 ounces of fluids a day. I had to start drinking warm decaf tea for a bit. I also found this sugar free caffeine free chai vanilla tea that I lived on for about a week...it was yummy so I was eager to drink.
Now I carry a 32 ounce water bottle with me that always has lime and cucumber sclices in it...very refreshing. Let me know how things go for you in the next few days. If you aren't able to drink more, definitely call your doctor.