iTunes automatically deleting videos when adding music

I am trying to copy music to my iPhone 5 after copying videos to it and when it "completes" the sync, the videos are gone from the iPhone and the music did not copy over (it shows it but does not copy actually copy). Now I'm able to copy the videos and it is fine It only happens when I try and copy music or other videos to it. Note, that if I copy music over and then videos, it removes the music and does not add the videos.

I cannot figure out why this is doing this. I am on IOS 6 only because I've heard that IOS 7 really slows down the iPhone. Any assistance would be greatly appreciated, thanks!

Things I've done...

restarted phone

restored a backup

removed all videos and music

it is set to manually sync

ran diagnostics in iTunes and it is reading "Ok"

I am on iTunes 12.1