I feel completely disconnected.

I'll start of by saying I've felt "not there" from time-to-time for years. It's been disconcerting at times, but never to the extent where I felt like panicking (if I wasn't too out-there to do so). I basically feel like I'm not here, at all.. My vision goes in and out. It's gets blurry, and won't focus. Sometimes I feel like when I close my eyes, that I'm going to fall forward, and my body just won't stay warm enough. I could stare off into space, and be completely oblivious to everything around minutes to an hour. I honestly feel like I'm lost and don't know where I am. My body just feels weird, but I don't know what is wrong with me?
It's gotten so bad that I just see myself as a walking shell with basic thoughts, and some physical pain.