I drink out of a med cup. The doctor gave us a huge supply of medical cups that are 30ml (one ounce). If I try to drink out of a Water bottle it causes too many gas bubbles and it feels like my esophagus is all weirded out.
I do drink out of a regular glass, which I can do my shakes out of or skim milk, but when it comes to water, I need to sip out of the med cup still. If you don't have those, try using a shot glass.
The one ounce cup I get 3 sips out of, and now I can do it in 2 sips. After 3 ounces of water in a row (sip after sip) I need a break.
Good luck, it gets better over time.