If I reinstall game do I lose all my progress?

Dem lvl 30 characters.

of course not, accounts are stored server side. =)

No you do not =). All you game data is stored on both you computer and on the steam cloud/servers. As such, at any given moment, should you want to uninstall and reinstall it will make no difference. Some games however do not save you configuration. ie, keyboard setups, video settings with resolutions etc etc.

it wont save! i reinstalled the game, and i lost all my progress… i cant do anything, this is sucks and wasting of money

You just need to finish or “leave” the prologue. It’s not possible to lose progress through reinstallation.