oh, L., life is too short to get so stressed out about something as shortlived as this.
set the worry free.
so the kid has water in a bottle - it's not the end of the world and your worth as a person isn't found in your kid's ability to drink from a sippy cup.
our little boy had a hard time letting go of his nighttime bottle.
we didn't really push it, just offered it less and less often.
don't stress about it, just give it time.
if, at the times you don't give it - or the times he takes water from something else (straws are helpful), tell him how proud of him you are for taking the big boy cup. ignore the times he refuses it. when there's no bottle, he's likely not to miss it.
we did use these juice bottles we found at target (still do).
we took out the apple juice in them and put in water.
he still loves them.
i like them bc they're no spill and can go anywhwere.
they have character heads on them - curious george, clifford, bob the builder...
i think they're called thirst quenchers of something like that - they're on the aisle with the apple juice.
usually down low.
you can get them other places too, but i've found target to pretty reliably have them.
we took out the juice, put in water and took off the label.
they are fun and don't leak.
best of luck.
just follow your intuition and no worries...it's not the end of the world.
now, go love on those babies while they're still little :).
s