What to do when supporting a friend with social anxiety triggers my own?

Hi. I've always suffered from anxiety and recently recovered from a severe bout of depression (by 'recovered' I mean that rather than being classed as severe, I'm now just moderately depressed), and was told by my doctor that my anxiety was probably a large factor in my depression and that I should be careful to monitor it, as it often leads to depression, which is IME much worse than anxiety on its own

I can now go to bars and order drinks and ask waiters questions, which I couldn't do before - I am generally not extremely socially anxious anymore. However, a friend of mine, my best friend, suffers from it too, and is reluctant to do anything other than entertain it, meaning that when I go out with her, I have to tailor events towards her if I want her to come - we always go to the same place at the same time. I don't mind doing this, but it stops others from doing what they want, me included, and I'm starting to think i wait around for people too much. It's incredibly selfish, but talking to her about her social anxiety - walking her through it - is often not just socially frustrating but makes me relive my own social anxiety. Now that I know she has it, i am the only person she talks to about it, and i don't want to pull the rug from underneath her bjt it's stressing me out. I find it difficult to confide in anyone at all, and I'd feel embarrassed if my hypothetical sole confidant told me they didn't want to talk about my issues anymore

I tend to respond to others' actions with introspection - I feel inadequate when my friends do well, for example. It's horrible and childish but i can't stop it. I'm wondering whether me not being able to cope with my friend's anxiety is just another example of me being self-centered, or if it's something that I should stay away from for the sake of my own mental health.