It's getting bad again.
Brush your teeth with warm water when it's cold outside, it will make you feel less empty
(at least for a few minutes)
Try to go outside at least once a day, even if it's the last thing you'd want to do.
Empty is not good. Empty is not good. Empty is not good.
Stop expecting so much from others. Expect more from yourself.
Things are not as horrible as 4 a.m. makes them seem. You are not as bad as midnight makes you believe.
The dull ache in your chest will go away. Or you'll stop noticing it. Either way, it gets better at some point.