I clicked git init in my users folder by mistake, and then everything in my users folder has been turned with a blue question mark.
How can I fix this?
Check the Documentation About git init
When you run git init, a new .git folder its created on your project directory with some other subdirectories for objects, refs/heads, refs/tags , since its a dot file (.git)its hidden by default, so if you are running linux do the following.
cd myFolder
rm -rf .git
If you are running Windows, there are bunch of tutorials to show hidden files, like this for example