D3857, have you communicated to the place that has you on the waiting list how urgently you need a psychiatrist? It seems odd that your therapy agency would simply quit on you without getting you care. My only thought is that perhaps they were angry that you left the hospital prematurely. I had a private therapist and psychiatrist quit on me when I refused to stay in an IOP (Intensive Outpatient Program). I ended up hospitalized in the end at that time.

If you're so unwell and can't get help from an outside therapist or psychiatrist, then maybe the hospital or an IOP may be the best choices. An IOP can be as little as four hours per day and a few days per week, so many in IOPs do still work part-time. If you're very ill, I should think your employer should understand and be flexible. If you're so unwell, I would think your employer may not want you to report to work in such a condition. Check with your HR. Many employers even offer private short-term disability. If not, then at least unpaid leave may be better than getting fired.