You can check your voting mana here: https://hiveblocks.com/@brutalmonkey

The reason is because a SteemMonster delegation for you has been withdrawn

you can check it here: https://hiveblocks.com/b/54585914#2d0e114d7cb2063ba949dc5292e71396debf19be

The mana power you had was probably derived from this delegation

Through the site https://giftgiver.site/ you can get a small delegation for a week, I did this procedure for you and with that your HivePower was increased by 12, with that your mana power returned to just over 50%. D