Whatsapp went missing and restarting iphone doesn't work. What to do i'm freaking desperate?

Iphone 5 restart more than 20 times never work.

No in the app stall it shows as open not download

Can you just reinstall the app from the app store? If it's missing it may have just be uninstalled.

Back up your iPhone with iTunes and then restore. Restore your backup and all of your problems should be resolved. A lot of the program files on apple devices get worn after a while and need to be reset. Nothing should be lost as long as you back up and then restore back up.

I've worked with apple devices for years and many times have I come up with the same problem.