If you did not close the modeler and have a lot of microflows, pages etc open with changes and you would then restart your computer you would indeed lose work. But when you close your modeler it will ask you to save unsaved changes.
Did you already do any commits to the teamserver? Because you could do a fresh download. You at least then have the latest commit version. And you might want to do some academy lessons about this topic.
Regards,
Ronald