@Jillygood
Sorry to read of your problems. One stress aggravates another.
If it is the dark that worries you, have you thought of using one of these LED nightlights?
In UK they cost about £10 and plug into a wall socket. Running cost is almost nil, they are about 3 watts only, and provide enough light on the landing for us to find our way from bedroom to toilet without falling over, or walking into, anything.
If you can manage it, having a pet for company is a great help, for the companionship that they bring. True, they cost for food and need attention, (Walking if a dog) but a cat, if kept in at night, for their good as well as yours, can be very companionable, so that you know that you are not alone.