Hot and cold behavior from friends really can suck, can make us feel crazy trying to sort out what is what.

Reading what you've written here - I don't believe that you are an idiot or stupid. I hear that you feel that way and I've certainly felt that way about myself too in the past.

Changing the way I talk about myself to myself makes a difference. Took awhile for me to develop the habit of being good to myself. And I have to be vigilant with it.

You know, you could slowly work on learning the cello just because you want to. Learning to play could be a constant habit you build and enjoy, no matter what temp - hot or cold - the people around you currently are.