I'm very sorry to here about your troubles.

It sounds like you've gotten some bad advise from people you thought were knowledgeable about garter snakes. It happens.
The forum care sheet is a great place to get the real scoop on garter snake care.
You are also welcome to post any questions you might have.
You have to do what you feel is right but don't kick yourself too hard.
Garter Snake Care Sheet - Caresheets