Something that has helped me is to work out a flexible schedule with my employer. I now work 80% (and took a 20% paycut) and also work from home one day a week. On my "day off" I run errands, clean house and try to take care of at least one extra thing that otherwise would never get checked off my to-do list. Also, I try to get done early so DS doesn't have to be in daycare a full day that day. On the day I work from home, I'm honestly too busy to catch up on laundry or run an errand over lunch (which I was hoping I could do) BUT my commute consists of dropping DS at daycare and picking him up, I don't have to worry about what I'm wearing, I don't need to put on makeup, and in warmer weather I just pull back my hair and don't bother styling it.
The days I do work and go into the office are long and hard (and DH does help a lot), but my day working at home and day off really make a difference. My house still isn't as clean as it used to be, my garden was very unkempt this summer, but I can do the things that keep me sane. And the weekends are for my family and I can take naps those days with DS and get caught up on sleep.
If a flexible schedule isn't an option for you, can you afford a cleaning service? If I had a full-time schedule and a full salary to match, the first thing I would do is hire someone to clean my house.
One other thing that helps me is that DH recently started taking DS one weekend morning and lets me sleep in as late as I want. This is heavenly!
Good luck. I hope you find some solutions that help you and your family.