Most likely your Resource Credit (or Mana) have gone close to 0%. 

Steem have undergone an update a week ago. One of which is the implementation of the Resource Credit system. With this in place, all comments/upvotes/transfers or any transactions happening on the Steem blockchain now costs some RC's. The more SP an account holds, the more Rescource Credits it will have.

Right now your RC is at 6% which would mean you could only do at least 1 vote and 1 transfer atm. Either power-up some Steem or wait for it to fully recharge to be able to post/comment once again. 

RC regenerates at a rate of 0.83333% per hour so yeah, in your case it would take around 5 days for it to fully recharge. :)