Did you try rebooting your watch? Mine dropped to a crazy 3 hrs of battery life; I put it in low power mode until I got home, rebooted it, let it charge, and now I’m nearly back to usual battery life (a healthy 65-75% at bedtime, after all-day usage and two 30-minute workout sessions).
After a few issues I unpaired my Apple Watch on Beta 2 and re-paired it and restored from backup. Now every card I add to my wallet says Card Unavailable. Try again in a few moments. from memory the only way I could fix this before was to set up the watch as new? Has anyone else experienced this?