Currently I don't get out much outside of work, I do go to meetups from time to time to meet new people but generally don't find anyone to "stick" with. I have attended university and completed a certificate there but never finished my degree, and any future formal educational plans are sort of out in the wind at the moment, though I am looking at more technical certification in I.T.

I feel like this is one of your biggest problems here, friend. Socializing fucking SUCKS, but the more practice you get and the more you learn about body language and facial cues, the better you'll be at dealing with social interactions.

You said you go out to meet ups every so often and school is out for now, have you gone to a class for something you like to do/want to learn? I mean for something light and practical, like learning how to surf, improv or an art class. Not something that you necessarily need to commit to, but something that lets you practice a few hours a week. Its a good way to expand your comfort zone, while still feeling relatively 'safe'. Learning and practicing something you enjoy will also help you make friends with people who have similar interests.

Basically what I'm looking for is some advice from people that have previously suffered from SAD that created debilitations in certain areas of life, and how you got past that.

How I got past it was working in food service, constantly having to go up to a table of people and asking them questions really helps you out. Of course, I had a lot of anxiety attacks in between, but that would have happened anyway, at least they happened for a good reason.

Then I worked the register in a small deli/restaurant. Having to deal with regulars and customers day in and day out really helps to normalize social interactions. By then, the only time I got anxiety attacks was when the boss came in (having someone staring at you, constantly feeling like you're being tested only made me do my job worse, which in turn got me in trouble, creating more anxiety).

I'm not a master extrovert or anything now, but I can at least maintain eye contact with people and make small talk with those around me when I feel the need. Try checking out /r/socialskills for some pointers!