Hello
@gillk and firstly welcome to this friendly and supportive forum. There is a wealth of shared experience of dementia to be found here, so I am glad you have found us, although sorry that you are stressing at 3.30 in the morning.
I am sorry to learn about your Mum's late stage dementia. It's certainly tough having a parent with this cruel disease. I had the same with my Mum.
If you are struggling, and you say that you don't know how long she can still remain at home, then it certainly sounds like you need to be considering more care, either in the home, or residential care. This link may help with information.:
Advice and practical tips for carers on when is the right time for a person to be moved to a care home.
www.alzheimers.org.uk
You have come to the right place for good advice, suggestions and total understanding as members here really do want to help. And you can always use this space to let off a bit of steam when you need to. Take care.