Question about apps please help

I have fairly bad anxiety so this is killing me right now. I downloaded an app from the App Store. The app was ok for months but now I see the app is no longer available on the App Store. I can still access it on my phone, but once you go into the App Store it’s not available any more.

im scared that maybe the app could hack my phone and get my personal information, maybe Apple removed it because it’s dodgy? Maybe I’m just being totally paranoid and worrying about nothing. It was an app that you could download music from the likes of YouTube.

Will my device be ok? Please tell me something nice.