I Came Down With Body Aches Rather Suddenly Yesterday Afternoon

I came down with body aches rather suddenly yesterday afternoon between 1 and 4 PM. I ate breakfast with a group of other retired guys in the morning but one one appeared ill. There was some nausua yesterday but that faded. It feels like a mild case of the flu but I don't have a fever. Aches are a bit better today but still here. Any ideas?