Added music disappears

[jbenecasa]

So, I have had spotify premium for a little while at the suggestion of my girlfriend and proceeded to save music and use it to find artists that I otherwise didn't know about. My issue lies herein: over the past couple weeks, I've added music to my artists list and when I went back the songs or artists were gone. I've gone through this a number of times over the past couple weeks and had to repeatedly add the same songs by the same artists, as if I had reached a certain capacity and would not be allowed past that. I have no idea why this is happening, particularly because of the fact that almost everyone else I know with spotify has not had this problem. 

Anybody have any suggestions or answers for me?