Hi Lizzygirl,
I think it's a great idea. If it will make you feel better, tell him in the email that you are doing this to give yourself a place to express your thoughts and feelings while he's away.
You're not being overly obsessed. When your T is your attachment figure absences can be quite difficult especially because if you never had a secure base, you never learned that the relationship will hold up through breaks. You're learning it now and it's a LOT harder when you're an adult.
If it will make you feel better, my T allows phone and email contact at all times including vacations (with the rare exception of him being out of the country and then he has been kind enough to tell me when he sets foot back on American soil so I can pounce.
) The last time we went through a five week break, I emailed him five times and called him twice. Now admittedly, I was seeing my mother for the first time in two and a half years and we were dealing with an ongoing family crisis so my contact level was higher than usual for a break but there it is. And I often use journaling especially when away from my T to sort through my feelings and keep a record of stuff I want to talk about when he gets back. And to really make you feel better? I actually keep a countdown calendar on my computer desktop counting down until my next appt because it makes me feel better to watch the numbers go down. There now don't you feel more normal?
AG