First, how many hours do you want to spend sewing on the weekend? You need rest & relaxation, too, and you're sewing all week, so why not start with just 4 - 6 hours total for a weekend. Decide on a specific time or times. It doesn't have to be the same time each day. Maybe Saturday night and Sunday morning.
Maybe combine it with laundry time, so you're sewing while things are washing and drying. Or with TV time.