Please Help. Is this a rebound relationship?

I was dumped 2 weeks ago after not hearing from my girlfriend the week before. Everything was wonderfull before that in our relationship. i recieved a e-mail during the week that told me she was in love with somebody else she just met. I am very confused at times why she did not give me a change to even talk to her and can Love become absolute overnight. I going through a very tough time but decide not to e-mail back as yet. I am realy concerned about her as she is a real fragile person and can it that this realtionship she just entered be a rebound relationship. She wrote in her mail that this is the man she want to spend the rest of her life with. I made some mistakes in our relationship as not wanted to commit to marriage as she have to finish her studies first.We were together for 2 years now and I know she loves me alot. Must I mail back or wait a week or two?

Dang, just E-mail her back.

I read a lot of post you recommened not to reply via e-mail and I dont know if that will really help. The thought of her having sex with this guy drives me nuts and that she really falls for him. Must I just let go?

talk to her, ask her if she's sure its over. if she says yes, then move on.