I just had 1/2 a mug of thera-flu for congestion and flu, which is supposedly non-drowsy. I only drank 1/2 a mug because the honey and lemon flavour tastes really gross, but since it said non-drowsy I chose it over the lemon flavoured variety. So, why is it that I'm feeling extremely sleepy now? I've only been awake for a few hours and I don't want to nap today. I think I'll play some mahjongg and try to stay awake now.