If they just sent you an e-mail it's most likely not something super serious. If it was something like that I'd imagine they'd call you at least. I know it's easier said than done, but try not to worry. When I have a situation like that I try and think of some scenarios good/bad and instead of focusing on the bad, I think how I'd deal with things. Therefore even though the chances of it being something really really bad are slim, I've still dealt with it a bit in my mind.
Oh and Jen, good work on the proper usage of 'eh'. I think we should make you an honourary Canadian