OnePlus X running lineage overheated lost all the contacts I have oneplus x and I have installed lineage OS for it. It has worked great, but today it got to some loop and the phone was hot. When I tried to open the lock screen, I only so program “whos in my wifi” and it was showing me some error “don’t member anymore. Some android.com… or something” and I could get pass off that error. So I restarted the phone and then everything was gone. All the settings, contacts, whatsapp messages were gone. But programs and most of the pictures where there. 

So any idea what to do? Is there fix or repair system program to run on recovery twrp? Or is it all gone? 

UPDATE

Now it did that again. I think I need to unistanll lineage OS...
If you manually didn't take any backups before (using TWRP, titanium Backup or any such app), no there is no way to get that information back. WhatsApp takes daily backups, so might get those back. Contacts are usually synced with your Google account. 

If you really want some content back, you can try apps like Undelete that can get back deleted files, but there it's difficult to track what system files you need to recover to get those messages back.