I'll add to everyone else's enthusiastic endorsement of TELL. They were a valuable resource; the responders there have been through harmful therapy themselves.

Leaving was difficult for many reasons: I HOPED this therapist would help me ease the pain of living; I saw him as a wise shaman authority figure. I left with much to unravel.

There's not too much literature covering bad therapy, but there are several on-line check-lists, including TELL's

Unsafe Poor Bad Psychotherapy | TELL: Therapy Exploitation Link Line
50 Warning Signs of Questionable Therapy and Counseling
What should NOT happen in therapy? | Supporting Safe Therapy
How therapists abuse their clients

All the best. On the good side, I perhaps learned more leaving bad therapy than I did when I was in it.