Nikki, if it makes you feel any better, I share almost exactly the same description as yours that I actually used search terms to find such a question looking for advice along similar lines. Only way I am different is I am a 32 years old male; I can't afford to work for less as I have a family to support. Also although I am quite a sociopath, this is of late making me more so due to my hearing loss on one side.
However, please do let me know if you find an answer to your problem, and I will also keep a watch on this thread for answers/advice from others. A job that would make me work close to animals while letting me also stay on the computer for much of the time so I don't lose my computer/programming skills for future security and keeping the society around me happy/less concerned! This will be paradise for me atleast in the short term! I haven't tried any volunteering yet, I guess mainly due to the same reasons as "introvertedness". Converting to vegetarianism is as far as I have gone towards animal welfare, but I know I would need to do more than this!