E-mail problem

Hi everyone!

There were some documents which should be sent to the Traineeship Office until today. I sent them yesterday and I've just received a message from gmail that the message was not delivered but it is delayed. I really worry that my documents won't arrive there in time and my application will be considered invalid. I've sent another e-mail (without the attachments) to the same address explaining the situation, but I'm still not sure if this was enough. What else do you think I can do? Can I trust in gmail that it sends my attachments in time?