I'm going to say as soon as possible. Though my situation is somewhat different from yours, I think it still applies.

After a mental breakdown I quit a 5-year job that I had hated all along. I told myself I needed some time to "get my life in order" because depression and anxiety was seriously ****ing with my ability to cope with everyday stress. I thought I'd take a few weeks or months, get some help and then get right back into it "when I felt ready."

It's been 2 years since then and I STILL don't feel "ready"! I haven't even started looking for a job. I feel like a broken person who nobody would hire, and I'm seriously deathly afraid of interviews. So I continue to procrastinate. I'm beginning to realize that I'm NEVER going to feel "ready" and really need to just get back into work, because I can't rely on my parents to support me my whole life. Much as I hate society, I tend to feel really guilty about not being a "contributing member."