photos not syncing on mac after keychain problem

I recently had an issue with the keychain on my mac--I was asked for a password, declined, got locked out of the keychain, logged in (my computer's password), reset the keychain. I had to remove imessage from icloud and put it back and restart the computer in order for it to work. Now photos is not syncing. The restarting did not help photos. My ipad synced the photos taken on my iphone. But nothing on the mac. I notice that something called "Photos agent" is using up significant power. Any advice on how to get it to sync (without deleting photos) would be appreciated. Thanks!

Specs: Macbook Air mid-2012 (dead battery), Mac OS High Sierra 10.13.1. Photos 3.0.