I don't recommend you to heat a brick, wrap it around a sheet and put it into your bed to warm you while you're asleep. Most probably the brick is too hot, it burns the sheet, it burns all the blankets, it burns the mattress and it can burn you. You will probably wake up too late when all the damage has been done. The room will be smoky as hell and you too sleepy to react fast enough. After extinguishing the fire you might be able to continue sleeping (though it will not be a pleasant sensation) and if not earlier then at the latest the next morning you will wake up to an awful feeling of throwing up. Actually you will throw up tons of times and feel constant pain in your body. All you can do is to lay down and drink water which will not stay inside your body for more than 5-10 minutes. If you go to see a doctor he says that you have been poisoned by the smoke and the only way to get better is just to breath the shit out of your body. The rest of the day will most probably be HELL. You can't walk, you can't stand, not even sit. Everything feels bad and the only thing you can think of is "I just want to die". The next day you will feel better, though not perfect but the third day should be fine again.
Greetings from a girl who has just been through all this... But I'm not going to let it pull me down. Our trip starts tomorrow, everything is packed, car is ready, plan is made, excitement is touchable and I am feeling fine again! Adios I say!