Some say pushing your sleep day back until you get to a normal time works. So, on the long weekend coming up you could try staying up until 3:00 in the morning, then 7:00am, then 3:00 in the afternoon, until you get to 9:00pm (or whatever normal sleeping time you want.) The theory is trying to fall asleep early doesn’t work, but exhausting yourself to get back onto a normal schedule is more likely to succeed.
They have done studies that show some people truly have a different circadium rythm, and going to sleep before midnight is just not natural for them.
I do have a question, are you tired suring the day, do you need a nap, or do you simply require less sleep? If you are easily living off of 5 hours sleep, you might want to get your thyroid checked if you have other symptoms like dry skin, dry eyes, hair falling out, etc. Probably not that though, since it seems your whole family has the problem.