I'm the exact same. I used to get 2 days use from a full charge. Now in the last while (possibly since the last update) my battery life has been much shorter.
Today I charged my battery to 100% at 8:00 and my watch ran out of battery around 13:00!!
I just updated the Gear app and the "Usage since last fully charged" only lists one entry, Contacts, and says it has used 92%?
Anyone else seen anything like this?