The next chance to re-sit is next Summer and you would have to re-sit all the History exams again.
If your panic attack was not obvious to the invigilators then I'm afraid there is little chance of special consideration. If you have one again then put your hand up and they could get you out of the room so you could calm down.
Go to talk to your Exam Officer anyway. Tell them you had an attack and talk to them about whether there is anything they could do to help in future. Mention the death as well and they will take it from there.