December Bills

I live on SSI and recently got a job at Subway to make extra money. However I messed up and worked too many hours and my check was docked much more than I can afford, and because of this I won't be able to pay the bills on December. It takes about 550$ to pay my bills not including grocery money. I have been trying to pay for a 500$ vet bill for my dogs heartworm treatment that is also due sometime in December. I have gotten my hours changed to adjust my check back to where it needs to be, but this won't come into affect until January. I would like to ask for a little help to make sure I can get everything paid for. All the money donated here will be going towards my house bills and groceries for the month,  if I use my subway money I should be able to pay off my vet bill by myself, but I can't do both.