[Q] Lollipop gets slow with FB app and FB Messenger app topic

Hi:)

After a few hours, Facebook app and FB messenger app gets extremely slow (G3 Lollipop, newest). Restarting the phone fixes the problem, but after a few hours, the same happens (gets slower and slower). But if it can start it, it runs perfectly (exept the messenger, its useless...).
Other problem: closing the Quick Circle phone case, the clock doesn't shows up, or just very slowly.

I ran Avast and Kasp. antiviruses, nothing:S

Any ideas?

Thanks for the help:)