Want to carry on working

I work 18 hours per week, in a job I love. My employer has put many things in place to enable me to go on working with my numerous medical conditions. I'm 62 and have been with the firm for 17 years. My dla was stopped last may, and I've been refused pip. I'm waiting for a date for the tribunal. I would still have been entitled to tax credits, as I'm over 60, but they no longer exist in my area. I've been refused universal credit as I earn too much! I earn £600 pcm and my bills are £800. That's not counting food , transport, credit card etc. I'm getting into terrible debt and don't know what to do. How can I be earning too much for universal credit?  I'm barely over the national living wage. Cab don't know what else to suggest. Please help.