Really don't know what to do anymore?(Long, but in need of urgent help?)?

sounds like they are being overdramatic about all of this. There is no reason for this argument to get out of hand as much as it did. It was just a tiff that was blown up to something huge. If they are going to let a friendship go so easy than they really may not be that great of friends. With all that aside I would say all you can do is apologize and not say anything mean anymore and eventually they will come around. Don't beg just apologize and give them some space. If they don't forgive eventually then screw them go find new friends you don't need them to live your life.