You're doing fine.
No, sipping ever so often won't stretch your pouch. You're told to sip sip sip because you won't be able to gulp or guzzle down liquids, your pouch is still to tender for that, and you can easily gulp air along with fluids. On the other hand, unless you sip ever so often, you won't be able to make the 64oz per day goal, and will get dehydrated.
As for cheating--don't make it a habit, but just once won't damage your pouch. However, certain kinds of food too early out than your pouch can adjust to, may be stressful for the pouch, so, even if you were okay this time, you just may

the next time.
Almost 2 weeks out, and at home, is when you start getting antsy because you are feeling better than last week, but you are still too weak to do anything for a certain amount of time, so your head starts playing games with you.
Hang in there, things will get better as you go along. (((((((HUGS)))))))