Go through all their toys and send all the old toys to the charity shop.
When sorting the laundry out, separate your children's small clothes in to bin bags and send to the charity shop.
Put bleach down the loo last thing at night.
Spray the bathroom surfaces with cleaner before breakfast & then wipe it down after you've eaten.
Put the dirty laundry in the washing machine & set the timer to come on at 6am so it's ready to hang out before you go out for the day.
Put another load on at teatime so it's ready to hang out before you go to bed.
Whilst watching tv, sort through paperwork into piles to keep, throw away & recycle.
When you go upstairs, take anything up that belongs upstairs and same vice versa.
When you make a cuppa, put away dishes, clear the sink, wipe surfaces etc while waiting for the kettle to boil.
Break the housework into chunks so it's easier to manage, it's understandable that you're feeling overwhelmed.