My heart goes out to you.
I do hope Mother Cat turns up soon.
I had a similar predicament with Mrs. Black my matriarch cat.
She always disappears for a week or so when she has her kittens.
But she always reappeared eventually.
I was finally able to catch her and she has her babies(her last litter ) are doing well in their forever home. She will be spayed as soon as the kittens are weaned. And the kittens are already ok'd to be sterilized too when the time comes. I am doing the happy dance for me and for them.
My thoughts and prayers are with you.
Please keep on "pestering" us.( Its a joke, You are not a pest at all!)
I am here for you too. I know how you feel and it helps so much to talk to those who have been where you are.
Love and Life,