There are actually quite a few different reasons for people to be devoid of emotion.
Abuse at an early age
Depression
Being a sociopath
And I'm sure there are others that just aren't coming to mind right now. We humans have a full range of stuff that can go wrong, don't we!
Do you remember EVER feeling love, hate, joy, etc.?
Is there a before and after to when your feelings shut down?
Sitting down with someone face to face would probably help you sort this out alot better, but this is a really good place to start, too.
Pat yourself on the back for trying to deal with this. Its hard to look in the mirror yourself, so please don't discount what you are trying to do to help yoursef!
Hope you get lots of ideas/viewpoints here so that you'll have a little to go on!