Hi and welcome Sam!
I can really relate. My mother had/ has anxiety, and depression. She was diagnosed 15 years ago and it got so bad, she weighed about 40kg when she was admitted to hospital (inability to eat due to anxiety). It is now well managed with medication, which took her a long time to find something that worked for her.
When I was in uni I was also diagnosed with depression - at first she was in denial that I might have depression, because I think she just didn't want me to have what she has.
But eventually when my GP prescribed anti-depressants it hit home. (The GP didn't tell her about the medication; I did. GPs have to be confidential).
What came out of it, is that in fact it has helped us bond, and I rely on her a lot for advice and support. Because she has 'been there, done that, got the meds' it isn't all new to her when I ask her about stuff. It has also been re-assuring, when I've been going through side-effects with new medication, to have her support (and past experience too).
You never know - perhaps in time to come this will add to your relationship with your Mum.
Great that you've made an appointment - I recommend you go see your GP. It is important you look after your health - physical as well as mental.
I wish you all the best!