Even when my 23 year old daughter is in the same room...I do not understand why my mom just won't say anything to her own granddaughter who loves her grandmother very much ? And my aunt acts like nobody has a name in the whole house except for Me & my 4 yr old grandson?
You might think about having your granddaughter gradually assume more responsibility and work more closely with you in care for your mother.
I know that some of the other posters will choke at this suggestion of bringing your GD closer and more participatory in care for your mother, but if she's willing and has the time, it may help your mother build up confidence in her.
I'm assuming that there are no neighbors or close friends who could stay with your mother when you need to go out? I wouldn't decrease the trips and shopping though, as you want to try to reach a balance in both your lives so that you too have freedom to get out when you need to.
There are some agencies that have companions who visit the homebound, but I suspect that your mother might not be comfortable with them until she gets to know them. And, still, they're not family and probably not prepared to intervene in the event your mother becomes anxious and unsettled.
Another way to decrease her anxiety is to try to relax her before you go, with music or something she enjoys doing. It sounds like a simplistic answer, and it is. I'm opposed to medication unless it's absolutely necessary; it may actually help, but I'd try something safer first. Meds have side effects and I avoid them as much as I can unless it's absolutely necessary. Just my opinion though.
In any case, something is wrong. Have you discussed this in detail with her doctor? Getting Mother help with the anxiety will be happier for everyone.
How does the aunt fit into this picture?
Without knowing more specifics, I can say that this sounds like anxiety. What is she calling to say? Is she starting to show signs of dementia?
In any case, the anxiety may need to be treated.
There are anti-depressants that treat anxiety without sedating effects. I would encourage you to speak to her doctor.
Without more information it is hard to make other suggestions.
Best of luck,
Margaret