Why did my files (Pictures, Music and apps) went missing??

[Re_B00t]

Recently happened. I tried opening an application and it stated "(Application name) has stopped working". I tried rebooting the phone "Firefly Mobile Aurii Secret Lite 6.0 Marshmallow" Then when it came on my device stated my 8gb microSd card was missing even if it was mounted properly.Then I noticed some apps were missing and my music are gone and so is the gallery which is picked clean 0. I tried looking in the settings to find what happened and found my sd card with 3.41gb occupied space with 3.93gb left available but it was not showing the data of apps, files, music or anything and it's completely invisible or something. I tried looking for my files in the file manager but to no luck. One thing I noticed in the file manager is that my internal storage is missing too and that my SD card is only the one showing up

 

[Rukbat]

Is the card formatted as internal or external? Rebooting (which means restarting, which does almost nothing)? Or reinstalling the ROM? Have you removed the card, put it into a PC and looked on it for files (which will only work if it's formatted as external)? Have you tried turning the phone off, waiting a minute, then turning it on? (It's difficult to guess with a non-name phone.)

 

[Re_B00t]

It's formatted to internal.