I had my surgery on Monday, too. I am having diarrhea also. I couldn't drink much that first three days either. I think I only had 12 ounces Wednesday, 26 ounces on Thursday, but today I have done much better. I am up to 40 already. I don't seem to have to sip anymore either. That kinds of scares me. I don't want to think now when I start to eat it will me the same.