My 16 week old boy has developed a really sticky sounding mouth at night time as if he is really thirsty. He is feeding (bf) fine so should be getting all the drink he needs, but even an extra 'drink' doesnt clear it. He also has a dry cough and then holds his breath for a few seconds and generally seems short of breath sometimes. He seems a bit mopey the past few days, but still has smiley chatty patches through the day so i dont know if I should be worrying or not. Help?