Glad to see the mention of steemd. A couple of times I thought post were lost, but a check of steemd showed it got saved, then clicking on it, and view in steemit, it magically appeared. So sometimes it is not completely lost, other times, yep, gone bye, hasta la vista, filed in file 13, or warehouse 13. Then it is time to re do it. It happens.
One other hint if your reply box is still pink with a spinny thing you can still highlight and copy your post. Then if the page says loading in the lower left hand side of the page you have it on your clip board to paste in a new post box. because once the "page loading" appears in the lower left of the page it is gone. Just reload the page and re-post. If you reload the page before you get the ominous message in the lower left of the page, then your message will still be in the message box, and you just click post again and hope.