Random Riddle: 11-6-2014

Sometimes I am feared; sometimes I am loved; sometimes you wish I was real; sometimes you are glad I left you but no matter what, I always come back. Although I always change, you may remember me but sometimes you don’t. You think you feel in me but you don’t; all you know is that you saw me once and you will see me again very soon.

What am I?
 

Riddle