Hi acute-ava and welcome to the forums :)
I personally know how tough it is to deal with mental illness, especially at this time of year. It is good you are seeing a therapist it sounds like you are burrying some stuff, even from yourself. It maybe a good idea to try and open up to your therapist. I struggle with this too, but it may help.
Everyone fears being alone. Heck as I am typing this I am scared I'll never get married and be alone. But I realise I am more scared about being sad and unhappy most of my lfie. So I decided to try be more open so I can find true happiness in myself. It is tough but I am still trying. It is ok if you don't want to share your diagnosis with everyone, it is your business not others. I have shared mine with close friends, not everyone.
I think mental illness can be a part of you but it doesn't define you. Plus it may not be life long illness as Theborderline said.