Oh man... I am so sorry. Happened to me way too many times so I feel your pain. Be it long important emails, parts of my university thesis, articles I wrote for websites... These mistakes have actually taught me to write everything longer than just a few lines in MS Word first and then just paste that in wherever it is supposed to be. That is also how I prepare my Steemit posts and sometimes even comments when they are longer. But five hours of hard work on such an elaborate post... mam that hurts :( Are you thinking about writing that post again?