I experienced the same thing and admittedly had a heart attack. I thought that maybe a rogue app I authorised had gone on a Steem spree and used up all of my bandwidth. What I experienced was even more frightening:

Recharging. Please wait 1066h 50m 36s.
used 217kb of 29.5kb

1066 hours is approximately 44 days. I was in disblief and then kept refreshing Steemd to see my bandwidth going back up.

Now it's showing for me:

used 221kb of 174mb

Everything is back to normal, but I do sporadically see this issue appearing when I try upvoting or commenting on things: RPCError: transaction expiration exception: but it appears to be happening infrequently and probably a side-effect of the spam attack.

I love Steem Cleaners, they are really doing this platform a solid and counteracting the low-quality and outright spam content in a way that means low reputation Steem users don't have to flag themselves. I've reported so many Steem accounts this week to Steem Cleaners.