Hello Claire, I have a neighbor who sometimes finds herself in a similar situation. In her case she has a very stressful, demanding job (and an unkind boss on top of that), and while she loves to cook, during the week she will tend to let things pile up to the point where it feels overwhelming to tackle it. Her solution is to invite someone over (like me) to lend a little 'moral support' and keep her company so she can feel better about starting her clean-up.
If you know someone who would be able to help you in that way, that is one idea.
Another tactic I've used with myself with messes or other things that seem overwhelming is to tell myself I don't need to 'finish' the task, but only work on it a little bit for a set amount of time. Five minutes, twenty minutes, whatever you feel up to. I tell myself that some progress is better than no progress. Sometimes, I'll keep going after the alloted time is up! I pick the easiest or most obvious thing to do first. If I need to mend something for example, I'll tell myself that I don't need to stitch it up today if I run out of time, but instead only set aside a threaded needle so that I'll be ready to stitch it up later.