(((((bigcasper)))))) First of all you are not stupid. Your are very intelligent and your words are wise.

How did you spend money you did not have? Check? Bank card? or what?

Ideas: See if the vet will put a hold on your payment. Explain to them what is up and what has happened. If the payment has been recorded you may even talk to the bank and see if they will wave the charges. Explain to them what has happened and your illness they may work with you. We do sometimes find good people in the outside world to work with us. Not saying that they will but they might. I wish you well. Hugs for your day.