Yesterday unity randomly started to work very slowly, when i try to do changes in my project unity freezes or starts loading and now it takes forever to open my project.
p.s it was a problem with one of my projects but i i still dont know why this happens.

Try deleting the entire Library folder from your project ( “YourProjectFolder/Library” ). This will force a reimport of all assets. Happened to me a few times and this always fixes it.
i tried doing it, project opened faster but then empty scenario appeared, then i tried to switch to my primary scenario but it was loading again.

trying to leave play mode

i think that its a problem with scenario