I drink chamomille tea, I feel much better. No worries, the chamomille is caffeine free. You can find these chamomille tea bags in supermarkets. Hope can be of help to you.
You can try drinking a glass of salty water in the morning (the salty water don't need to be concentrate, very 淡 is ok). Try 2 or 3 days then you will become less 'hot gas'.