:(. I don't know what you should do but wanted to drop a note and say that I feel for you and I hope things go alright.
You can probably start oil pulling first thing in the morning; that is inexpensive and supposed to help with bacteria in your mouth. I'm not sure if it will help in your case and how long it takes to help and if you have that time, but it can't hurt. Do a google search on oil pulling to get started, it's easy and you can use any oil you have at home.
Brush your teeth with baking soda not toothpaste. Brush after every meal.
These are very cheap methods to care for yourself. I am not sure whether they will heal your tooth but they *may* help and they certainly won't hurt.