The thing about academia (and life in general) is that knowing what you are capable of...means bugger all. You aren't admitted to PhD program based upon the strength of you knowing that you can cope with grad school: you are admitted based upon the actual, physical & tangible things that you have produced. Publications, graduate-level written work, grades on a transcript, LORs that judge your actual output. You don't get tenure because you know that you are capable of being a successful research professor - you have to actually be a successful research professor.
My strong suspicion is that if you struggled with the MA, you will struggle also with the PhD. It is easy to correct mistakes - read theses before you start your program, take a break between transitions - but the underlying personal characteristics you possess are harder to change. Mental illness is a chronic thing, if it pops up during your MA it will return for your PhD. The characteristic of under-estimating what you're letting yourself in for will most likely show up in some form or other during the PhD.
It is dangerously naive to just assume that your idealised version of yourself will flourish in the PhD program: you need to ask yourself the brutal question of 'Would the version of myself that existed during the MA program, whom my advisor saw...would that version survive a PhD program?" Because although that version of you is the worst-case, nightmare scenario that can't possibly be the real you...that's the version that has a basis in reality. If an outsider read your narrative and examined your physical output, then extrapolated a prediction of future academic success based entirely on those physical/tangible things...what do you think they would predict?
I am by nature a deeply cynical person. I do know that people can change themselves - but it takes years, a lot of determination and willingness to accept complete responsibility for your actions. We can hide but we can't fully erase our weaknesses.
Personally I think that your advisors refusal to write you LORs for PhD programs might be the biggest gift they've given you. Don't ruin the next decade of your life attempting to do something that will only damage you.