Items turned weird and I turned invisible

I was messing around with some command blocks using it to enchant armor a little bit easier and all of a sudden everything went insane. First all of the graphics disappeared and was replaced with the purple and black missing texture thing. then a bunch of random weird things happened I kind of forgot. When the thing was over, I realized I was invisible and one of my items was different.

 

For some reason I can't reproduce it. and when I logged out and came back in everything was normal again.