Please help? Game deleting of PS4 system.

Hello everyone! So, I'm hoping someone here has run into this issue before and can help me...

Today, for the second time in 2 months, FFXIV has vanished off my PS4. I let it go the first time, thinking that in my distraction I had selected "Delete Application" instead of "Close Application". I now realize that isn't the case, as today I didn't select any option - I pressed the PS button to return to my home screen and immediately pulled up Hulu+. After one 45 minute episode, I went back to my home screen... FFXIV was gone. I restarted my PS4, I turned it off for 5 minutes then turned it back on... nothing. It's gone. It's the only game gone.

So, any ideas? Has anyone run into this before and discovered a solution? Thanks for your time, hoping you can help...

I believe you may need to replace your hard drive =/

Is it possible that it just got moved to your Library? Granted, even if it did that would be extrordinary in and of itself. It's possible that the data is getting corrupted for some odd reason. Either that or Hulu+ is Galactus, Eater of Worlds and hungers for the realm of Eorzea.

Is replacing the harddrive difficult/expensive? :/

PS4 is designed so changing HDD is easy. Please look for online guides (plenty around).
HDD costs will vary depending on your country, but 1TB Hybrid HDD shouldn't be that expensive unless you go SSD.

You will need to a backup of your existing data by USB to an external HDD first.

Thank you!!!