People outgrow friends just like they outgrow clothes. If a friend is so high maintenance that she leaves you feeling bad about yourself, it might be good to make some new friends and be less available to her. You don't owe her a lifelong friendship on her terms just because she was there for you when you were suicidal, and she should not hold that over your head. Any decent person would be there for you, so don't let make you feel indebted.

If she asks why you aren't there so much, tell her honestly why. If she's a true friend she'll try to be better to you. If she isn't, let her go. You don't need that.