I'm going to point out the obvious here, but if you're boyfriend is a mechanic shouldn't he know what the problem is or do super cheap rates on repairing the car without a need for insurance/credit?

I'm a little disturbed that this Mechanic boyfriend that was with you allowed you to drive home after that. Even if it was a few hundred metres away, if the oils gone then it's metal on metal & that's pretty much the recipe for destruction.