If you are getting a call from the gp, I would ask for a urine test what ever the diagnosis.
As others have said, after the phone and assuming it confirms your fears, do ring the Alzheimer's Society. They have lots of resources on line, fact sheets etc but if you ring up you will be able to talk to a trained Dementia Support Worker and arrange to keep in contact.
In Leicestershire there are Carer's courses being run on Zoom. I imagine other areas are doing the same.
Again, as others have said, Talking Point, on the Alzheimer's website, is an active forum with, mostly, Carer's interacting. I know lots of people on gn recommend it.