I wouldn't give up on using temp/employment services. When I first got out of the military in 1990, and every time I've moved (a few), I've found almost all of my jobs through temp services. Like you, my social skills have never been great, in my case thanks to severe allergies and allergy induced asthma. And I didn't have a network of people to help locate a job. Without temp services it would have been probably 10 times tougher for me to find work.
One thing I'd suggest, when applying at temp services, try to get in the door to talk to them face to face. Most of them want applicants to apply on their website, but some how, some way, you need to personalize it by meeting them in person. And after applying, testing and filling out all the required paperwork, make sure you continue to call back once a week. I used to ask them what day of the week was best to call. For some it was Friday, others a different day. Alot of employers prefer going through temp services. There are companies who will tell you they aren't hiring, yet have orders in with a temp service to fill a position. It could be just a temp position, or a temp to hire position. Unfortunately, some of those temp to hire positions can last for two or three years before a person is hired in, but at least it would be a start until you can find a better or long term job.
And when applying at temp services make sure they understand you'll take vitually anything. Maybe you have, but what may have happened is that they saw your degree and figured that's what you wanted to do. I realize in those situations it can be nerve-wracking for a more introverted person to express and be clear on what they are looking for, but it's critical that they understand. Even if it's just an $8/hour clerical job, at least that would be a start and gain you job experience. Obviously having a degree you wouldn't want to stay in a low paying clerical job forever, but until you can find a job in your field you'll have some money coming in.
Any temp service you've applied at, call them and let them know you are still available. And ask if they mind if you call them once a week to stay in touch in case something comes up. Another idea might be to ask them if they need you to train on certain software programs. Temp services will often let people train in their office using the services' computers and training/testing software. Often for simple office jobs you need to know certain software and test at an acceptable level. That would also make the temp service see you are motivated to find a job.
When I first moved to Omaha, Nebraska, I had some bad experiences with temp services. The next to last one I applied at was really bad. The lady could not have been ruder. I had a great work history, including six years in the Navy, and a good work history for over a decade after my military service. She acted like I had done nothing. Told me after I found a job, they might be able to find work for me.
It bothered me alot considering I needed a job bad.
The next day, a Friday, I layed in bed thinking, maybe I'll just wait until next Monday to try again. I was defeated. But something made me get up anyway, get showered, and I started calling other employment services. It just so happened Mutual of Omaha had a couple of temp positions starting the following Monday, and a particular temp service that I called had the contract and was desperate to fill the positions. I was in luck. I took their tests, filled out the paperwork and got the job. Ended up working three different assignments over a three and a half year period at Mutual of Omaha, before moving.
That's also a testament to the fact the temp services often forget about people already in their system. I'm sure they had qualified people already in their system who were available, but instead of calling them, they took a couple of new people. So stay in touch after applying.
Also, this time of year, maybe seasonal work at department stores, etc., will be available soon.
Good luck and don't give up or get too discouraged. We are pulling for you. So when you feel nervous while waiting for an interview or whatever, remember there are people who wish you the best. And don't look at the interviewer as the enemy who wants to judge you harshly. They are only doing their job, and want to find a good person to fill the position.
Let us know how your job search turns out.