So yesterday I finally got up the nerve to ask my new boss if I could take off early one day a week to see T (T's been seeing me in the evening since I changed jobs). And he said yes!!! I was
so worried that I'd be asking for something they couldn't do. T was willing to see me after hours but didn't really want to do that forever. I've only been at my new job for 2 months now, but T had a 4:15 appointment on Thursdays (hard to get!) that sounded like it might be workable. It was painfully difficult for me to get up the nerve to ask my boss if I could leave at 3:30 on Thursdays (in exchange for working later other nights), but he was fine with it. So now I can go to therapy and not even have to go back to work afterward (I used to go over lunch, but T's office isn't that close to where I work now).
I'm very happy about this. Makes me like my new job more too.

Wish it weren't so far to T's office, but I took what I could find.
I told my new boss the truth. Specifically I said I see a "mental health professional" every week. For some reason that seemed a better way to go than saying "therapist" I don't know why. But I had wondered whether it was best to tell the truth or not. He didn't seem bothered by it in the least. Didn't ask for documentation or anything. Just said it was fine and to let him know if anything changed (like if I needed to go at a different time or something).
Well I can't even tell you how happy I am about this. And in exchange of course I'll do really good work and be available late on the other nights if there's any kind of crisis.

In fact, I think I'll be the most pleasant employee around.
Sidony