I haven't played Witcher 3 for about 2 months because I had a hard drive fail on me making it impossible to recover what I had saved on it. Now I got a replacement HDD and fired up GOG Galaxy to install game I figured my saved games would be on there. All gone :(, all I have to show for now is the achievements that were completed.. I had 60+ hours into the game kind of rough to do it all over again.

There is no cloud saving (perhaps it will come in future). Sorry. Search for someone who can offer you a savegame which is close to yours or you have to restart.

Aw thanks yea that's unfortunate I guess probably won't be touching the game for a while then.

I had a similar issue at launch, and the game was giving me a LOT of trouble. I couldn't play it without constant crashing until 1.07, so it took me about 30 hours to get 15 hours into the game, and then I had to reinstall a new HDD with a complete new system build.
Took me a while to get around to starting the game again, especially due to the crashing and the fact that the early game is very weak in comparison to the rest.

Sorry to hear about your loss :(
I hate it when this happens to me... but i'm usually running like before three or four hours later (depending how fast i can get the replacement HD/SSD).

People... backup your systems. Yes, a decent backup software costs a few bucks.
I'm using Acronis (but there are others out there). My daily incremental backups can even run while playing, no noticable performance loss.
If i wanted i could bring back a single savegame from four weeks ago.

Do yourselves a favour... do backups.
Use some freeware if you want, do a disc mirror once a week... just do something.
Maybe someday you'll lose something important, not just a savegame...