Causes for the flashing lights??

Daschelle • Expecting rainbow 🌈 baby on December 22nd! So very excited 💖☺️

Im currently 33+2 and have noticed that i have begun seeing these flashing balls of lights go across my vision. This usually only happens for about 20 seconds before i notice they disappear. Could this be a sign of preeclampsia? My blood pressure is always actually really low and this is my first pregnancy so idk if seeing the lights at all would be a problem or since i see them for a just a second i should be okay?