I think the term 'nervous breakdown' is an outdated one not used medically these days, but I still personally felt like that was the best way I could describe what happened to me. I think if you feel it describes what happened to you and you feel okay using that term then you should feel free to use it - if you don't then don't.

I too hope that 'friend' is out of your life, and I'm glad to read you came through that bad patch.