Personally, I think the biggest issue here is that, you seem to be her only friend. I don’t know if your friend is getting therapy/medication for (not just the ADHD), but the depression and anxiety. But that would be a step that would greatly benefit her.
It’s never enough to just have 1 friend to rely on. It’s so helpful for our mental health to … be outside and see things and meet people. The more bridges we connect, the more perspectives we experience, can all help us heal from bad experiences in various ways.
You’re her friend yes! And that’s wonderful! And we all need close friends to love and cherish. But we also need a social circle, even if it’s a small one. You, personally, cannot be switch on all the time to be her one pillar of support. (I’m not saying give up on a friendship. Not at all. But you’re tired. You’re a mental health worker. You should understand how you, too, need to have some focus on your own mental health where you give yourself some distance to make sure you don’t over tax yourself too.)
Sometimes we just need breaks from people. I’ve done it in the past where I’ve reached my limit for social interaction and went totally radio silent. No phone, no internet. Just me and everything I need to recharge my mental health, as an ADHDer. But when depression is factored in, yeah that’s more concerning;;
Do you live close? Or close enough to travel? Consider arranging a day out every now and then, where you can do something fun instead of just calling/messaging. Where you can do a positive thing, maybe a club once a month, or something where you can just spend time together and reconnect. (If not, then maybe a video call on Discord or Skype, etc).
We all need friends, but we also have to take care of ourselves too. Both you, and her.
If you’re reaching a point you’re making yourself ill/tired. You need to then step back and focus on your mental health. You can’t support anyone if you’re not also looking after yourself. <3