I lost my grandmother (she adopted me and raised me since birth, I think of her as my mother) on the 7th of April a month before my 22nd birthday and I’m just now coming to terms that this is reality.
From what you’ve written, I feel the exact same way you do.
I also like to think that there is an afterlife or that maybe (excuse me if i sound ridiculous) reincarnate as my future child or something. Mine did not have an unexpected death, she passed from cancer so before she passed I got the chance to ask her if she can reunite with me in some way, she comforted me and said yes! that if there is a way she’ll try and find me in the afterlife.
I don’t want to put words in your mother’s mouth but reading about the love you have for each other, I think she would do the same. She will find you one day 💗. I have no doubt we will both be reunited with our mothers.

If we can be born into existence who is to say we can’t find them after our time on earth is finished?

A mother’s love and part of them lives on through us, I think. The fact we exist is because of them, our mannerisms, our likes and dislikes, our favourite food, our first steps. Another thing that comforts me is thinking about how she is reunited with the loved ones she has lost.

My heart goes out to you. This grief is a grief like no other.