Choose a day when you are not schooling and watch one of your children closely.
Don't change what they are doing, or talk to them about what you are doing, just watch them.
Make a list (mentally or on paper) of all the 'educational' things they do and what they potentially learn from it.
Made bed (life skills, character values: responsibility, diligence)
played with lego with brother (maths, spatial reasoning, 3d sculpture, social skills)
bounced on trampoline playing pirates with sister (PE, kinesthetic activity, interpersonal relations, drama)
and on and on....
At the end of the day, look at the list.
Then relax and realise that your children are learning every day, even if you don't get all the 'educational stuff' done!