When my Mum was diagnosed with her illness, I faced a crushing loneliness. I realised, at least subconsciously, that no person is permanent.
I learned, without knowing it, that comfort is temporary and that I would have to, on some level, learn how to fulfil the role of Mother to myself, and my siblings.
I then found that is impossible. Nobody can learn how to be a Mother in replacement of a Mother.
You need to find pieces of people you have lost in the people and places around you. Find somebody you can turn to for relationship advice, somewhere you can feel the comfort you felt with her, a person to care for you. Keep collecting pieces of her until you almost feel whole again. Don't be afraid to need people.
It's a challenging journey, and it doesn't get easier. It has been one year now since I lost my person. At the beginning the pain is omnipresent, all-encompassing, but eventually you numb to it. Not because it is less painful, but because you have forgotten how it feels to have her around, to hear her voice. You learn to be less comfortable and less whole.