music disappearing????

[Livewire]

I had Meridian installed on my phone, and it caused me nothing but problems basically. i uninstalled it, and just used the music app. then, my music app showed that NO music was there, altho it showed up on the SD card! so i installed btunes, and that showed the music, and then today, the music there just went away too, altho later it showed up again. THOUGHTS?????