For the sake of internet disclaimers and all that crap, I'm more professional than professionals but don't listen to anything I say. Ever.
I experience similar feelings with the world and "reality". The good news is, this type of feeling is "usually" a co-existing condition riding on the back of anxiety or depression. Ok, not good news.
It sounds like it could be loosely defined as Depersonalization disorder.
A specific in my case, it happens when I have nobody to talk to for long periods of time. And by this I mean really talk to, not people I am forced to associate with in whatever character I need to be at the time. An analog to this feeling can be read about: The effects of solitary confinement on prisoners.
Now this may sound extreme to people who don't understand, but at the worst the two are almost interchangeable. Only in the case of the free person, you are not at the mercy of the lock and key of the "justice" system, you have hope to stand up and join the rest of the world (Which can be just as bad as any justice system at times). You should always maintain hope. A good form of practicing hope is to focus on your basic needs and take care of yourself, keep your health and you will keep your mind. Smoke some pot and listen to music, enjoy a movie. Cut down on the booze.
I agree that drugs are not the answer (prescribed drugs included). You need to fix the problems, not drown out the symptoms. You could be diagnosed with a variety of crap based on a "statistical manual" and a "professional" human interpretation of these statistics compared against the information you give them. This is not a good reason for a chemical lobotomy.
Try to get as comfortable with yourself as you can. This is not so you can be alone, it's so when you are alone you can maintain until you find a function.
(again, don't listen to me though)