Q: Itunes

I was playing one of my play list on my Imac when a whole album that I purchased was gone.  I have about 7 playlist I listen to. So I went to them all and it was gone. But the crazy thing was the song I really love is "I put a spell on you" was replaced with a 25 page document of song list with words and a picture. I have spent lots of money on itunes how can this happen?  I have an IMac, MacPro, Ipod,Ipad, Iphone 6 plus. I believe in the product that is why I stick with Apple. Never had a problem before this.

Hope someone can help me