What is this that I'm in ?

I'm in something but I'm not quite sure what it is. I know love is involved, I think some people call it a relationship. I thought I knew the definition of that, I guess I was wrong but now I know that what I am in is not a relationship. What ever it is, it's toxic to my health and Im screaming let me out but my emotions cant bear the pain so I stay. Im losing sleep at night. Im having nightmares I shouldn't feel miserable, how can one person have such an effect on you that’s making you literally sick inside. I don’t feel connected. I feel that we are on two different levels, better yet two different worlds. Faith and now trust is no longer there anymore. Time is being wasted, and I wont wait around forever for change. I know someone else who just want to experience love will love to take my place. At this point I'm just disgusted and fed up with the behavior. Isn't it amazing how you can tell someone something for so many years that can improve the relationship your in, and yet they just don't get it . . . don't get it don't get it.