Sounds like "fungal gnats" to me. Do you have house plants? These pesky gnats tend to thrive in moist soil. I'm having an issue with them in my house plants right now. They will fly around fruit too if it's on your kitchen counter. You can get rid of them by setting out gnat traps in small dishes. Just mix up 2 pints of water, 2 tablespoons apple cider vinegar, 1 teaspoon sugar, and a couple drops of dish soap...stir it up and put it out in some little bowls (pudding dishes work great) around your house. The gnats will be drawn to it and drown. Works really well.