Unless a real fly is trapped in your bedroom and your unconscious incorporated its annoying noise into your dream, flies in dreams evoke images of persistence, speed and relentless pursuit; they may also symbolize nagging, unwelcome people that you know or the need to be aware of certain negative aspects in your life. In addition, a fly can also represent limiting ideas or an unproductive use of energy; someone might be a‘fly in the ointment’ and ruining things for you.
If a fly settles on the wall in your dream, do you wish you could discover the details about something or if everyone in your dream is swatting away flies for you do you feel smart as in no flies on him?
Blood-sucking insects such as gnats, midges or mosquitoes may represent instincts from the unconscious, the water from which they are bred and the darkness in which they thrive. Symbols of irritation, gnats, midges and mosquitoes, like flies, violate the intimacy of their victims and feed off their blood. Is there someone in your waking life who is sucking you dry and draining you of energy?... The Element Encyclopedia