I highly doubt it is 2.2 because it has been out for awhile and way more people have not had the problem. But you are definitely not alone. From random battery drains for no reason to upgrades causing battery drains. I had the problem when I upgraded to 2.0 and had to unpair/re-pair to fix. Some can fix with a cold boot. I haven't had a problem with battery drain since 2.0 and I am on 2.2 beta 2 now. Still stinks for anyone getting it.
Some people have had problems with their music causing all sorts of problems.
Hope your watch gets fixed fast.