My amalgam fell out; do I not need to go to the dentist right away?

My amalgam filling suddenly fell out.
I'm a bit worried because I can't go to the dentist right now.
I barely have any pain right now, but I am still anxious.
I feel a slight chill when eating.
If I just leave this, will it rot further or cause problems?
I'm wondering if I usually have to go right away, or if a few days is okay.
I would appreciate advice from those with experience.