if you don't have any nonimmigration status when your I-485
is denied,you can't file another immigration application unless you become a spouse of an American
citizen,if you overstay in USA more than 180 days since the denial of your I-485,You won't come back to USA if you leave.
If you submit an appeal,you may stay in USA until the
decision of the appeal is made. But if you lost,you will be counted the period of overstay since the date
of denial on your I-485