Hi, I'd like to help you with your question.
It sounds like you are experiencing caregiver burnout, a very common problem for people who care for a disabled or elderly person. Between the worry, the work and the need for constant attention, it is easy to see why you would experience this problem. In caring for your elderly mother, you get no breaks. Being the sole source of support for someone is draining and difficult.
There are many resources you can rely on to help. Is there a Department of Aging near you? If so, contact them about what services they can offer you. You can get Meals on Wheels, ACCESS transportation, help in the home with cleaning and shopping and many other services. They may also be able to provide someone to stay with your mother while you take a break. Some Dept of Aging agencies also have a caregivers program that offer income for you to help you care for your mother in the home. Depending on the size and funding of your local aging office, they may offer this as well.
Can your mother attend a senior center program? You may be able to have her stay there while you work. The Dept. of Aging will be able to help you find one close to you.
There are also many support groups available. Here is a link to help you find one. Within the help guide, there are many links to more resources as well.
Your mother's doctor may also be another resource to help you. Ask her doctor what services are available in your area to help you care for your mother.
I hope this has helped you,