Hi H, I wanted to say welcome to healing well forum. I hope that this will help you to find some sort of healing in some way.
You have already been through so much in your short life. Do you have insurance coverage? If so I would definitely take atedogs suggestion and see a psychiatrist and see about medications again. If you have been diagnosed with depression at the age of 13 and are now 18 and unmedicated chances are that your depression is only going to get worse. It is not curable all of a sudden. You need to seek help. If you don't have insurance your school should be able to help in some way. Please look into this.