[RadioKid]

If your "health card" is issued in Japan and sure to be issued, you can get tentative health card before your health card being issued.

When you can convince the doctor some how that the health card is surely issued within this month, doctor (or staff) will accept your card in advance.

Though I can say nothing about medical matters, I'm afraid you could have too mush meal and cold drinks. Warm green tea will be no harm and calm yourself.