Thank you for what you have written! If I could maintain a thought and/or concentrate long enough, those words would have been written by me. With that said, you are not me, nor I you, so, from reading what was written, I would say a near defiant yes to Introvert. Generally speaking, there are many people who enjoy being by themselves, and that is NORMAL, it is OKAY. Apparently you were diagnosed with depression; how long have you been HAVING problems with depression? Do you know what brought it about? Were you generally a LONER as a child?
As far as an Isolationist, very possibly, not! Remember, you are a human being, an individual, so don't let society, consciously or subconsciously, dictate how you SHOULD be. Do you have any other diagnosis? From reading what you wrote, you seem a pretty normal person.
I will end for now. If you wish, you may send me a private message.
Have a Great week!
Peace!
ADHD1956