im so sorry, I had one (you probably know) about 17 days ago, mine was from drug abuse.
You have to be careful with the using xanax here and there. It is a very powerful anti seizer med (all benzos are) and when stopped they can bring about seizers. Even small amounts.
Effexor is the other one that raises a flag to me (IMHO ) anti depressents are bad for people who are prone to seizers. You might have been on the border on being one of those people, its hard to say.
Your neuroligist will probaly have more to say on the matter. They're usually pretty good at pin pointing the cause.
Alcohol abuse also, can cause seizers in people who normally dont have seizers.
keep us up to date.. ((kittens)) sorry it happened to you.
love Joe