To keep working or not

My husband and I are already in our 40's while our kids are still in their preschool years. I know, it's late. We got married late and had kids after 5 years pa. It was good the first 2 years with kids, but as time goes by, it is getting harder and harder to find reliable yaya's/kasambahays. I have an ok lang paying job. Hubby's woks is on a contractual basis. Soon, our kids will be going to big school. I am already considering quitting work as I am often on leave since a year ago anyway to attend to my kids and my mom who is already 70+ y/o. Meantime, work at the office is piling up.