This looks like fun, I'll try to be very detailed. (I'll be answering in base stats.)
-HP: It has been years since I last got sick, and I eat decently as far as quality of food. 120
-Attack: I am not the strongest, but I can hold my own. 90
-Defense: I have more or less been a stress release punching bag for friends for years, it has been shown many times that when I fight or wrestle around I will be bleeding LONG before anything actually hurts. 140
-Special Attack: I am not the smartest person, but I did take some AP classes in high school. 115
-Special Defense: I don't get my feelings hurt very often, but I do have large burts of anger quite often. 75
-Speed: I have packed on quite a few pounds over the last 2-3 years, combine that with my psoriatic arthritis and I can't move very fast. 45
-Ability: Would probably be Thick Fat, because I handle cold temperatures EXTREMELY well. A second possibilty would be Rock Head, I grew up hitting my head on things, whether it be a metal pole for a Basketball hoop at school, or concrete because I'm not paying attention while walking backwards. It never hurts.
-Type(s): I would have to go with a Steel/Dark typing, because I take hits like there is no tomorrow. I also tend to have views and opinions that most people wouldn't like. Plus, the fact that I keep to myself nearly all of the time.
-Tier: Well, with a Base Stat Total of 585, I sound like a decent choice. Though that lack of speed, as well a 4x weakness to fighting would probably drop me down to UU or RU.