Hi,
First just to say that's an awful situation and I hope you're feeling alright! I think it ought to be a definite extenuating circumstance, although you may need to provide evidence to prove the incident, which may be tricky. Speak to the head of exams in your college and ask their advice.
Hope you went alright today, nobody can be expected to perform to their best with that happening, and I really hope you got the grades you needed regardless. May be an idea to send a letter to the uni directly and inform of the issue so they know what to expect on results day :-)