Hi K - I am currently at your preop weight - 307 - hoping to have the surgery this summer. I can't say "I've been there" but I will say that things that matter are almost never easy. I'm so sorry you're have a tough time, but it seems from reading on the site, that this is something that can clear up with time.
You made the right choice - it doesn't work any other way (okay 5% of the people get it to work - but 95% of them don't). Give it time, don't doubt yourself - regain a positive attitude and be careful not to get dehydrated - keep in touch with your surgeon's office about this. Be kind to yourself - this will work out.