I do understand your situation, and any advice I offer is not based on eventual success getting a job after SSDI. I'm still on SSDI, and have been for 8 years. I'm now 46 years old.
I know from the long-ago past when I returned to my old job (when I still had it) after periods in the hospital and Intensive Outpatient Programs that anxiety was my biggest challenge. That followed by poor sleep, maybe poor eating, and lack of support system to a lesser degree. So I know what my downfalls were. You've already indicated the anxiety part. I think the weapon we both need is anxiety killing skills. Definitely building a better support system (therapist, therapist, and psychiatrist to a lesser degree) is important. How often do you see your therapist? Can you manage to see him/her more often in the interim? Write down anxiety coping tools so you can see them, and set up reminders to use them. Practice really helps. I found Cognitive Behavioral Therapy tools to be especially helpful at combating anxiety/cognitive distortions (catastrophizing, all or nothing thinking, black or white thinking, jumping to conclusions, and others). Challenging paranoia is also a big deal for some people.
So I've been doing well, and am going to soon take some steps forward, too. For me, I'll start with volunteering. Believe me, I've volunteered in the past and failed at that. This time, however, I'm ready with my tools, and have learned a bit about why I failed. I'm hoping that that knowledge will increase my chances of success this next time.