The possibility of fruit flies exists, but there are several other species of small flies that infest homes this time of year as they look for safe places to overwinter their eggs.
The easiest way to tell if they are fruit flies is to get a narrow necked clear disposable bottle, such as bottled water or cleaners come in, rinse it thouroughly, and leave a half inch or so of apple cider vinegar in it overnight. If you don't catch half a dozen or more, research
Fungus gnat - Wikipedia, the free encyclopedia Psychodidae - Wikipedia, the free encyclopedia Phoridae - Wikipedia, the free encyclopedia
One of these may be your culprit