With any task that you don't wish to do, break it down into small parts.

Don't think about the whole task at hand.

Now, what's the first thing you would need to do, in getting ready to figure this out?

I would think you might need to gather all the bills together, or at least have a list of all the amounts DUE and when they are due.

That's all you have to do right now. You can do that. Don't think about any of the rest of the job.