I didn't have a lot of problems when I left. I was just so happy have it out of my life. However to this day I hardly look at a WT with angry. They are so full of crap. I think how you deal with it when you leave depends on a lot of things like if you were born into it, how long you were in and what type of witnesses you had to deal with when you were a JW. A person who was raise in had to go to school and not salute the flag, participate in school activities, avoid holiday, waste their weekends at meeting and in service etc. That is lot of pressure for a kid to deal with.
Dont' be to hard on your girl friend for not understanding. A person who has not been in a cult has no idea what harm they can do. They tend to view it the same way as someone leaving the Baptist or Catholic church.