Overwhelmed by what you need to do or want to do? You have to decide what is more important. Sometimes you take more joy from doing what you want to do than what you have to do, so what you have to do is a chore and seems less important. So that may be the overwhelming part.
Obviously if this is causing such a problem for you, you will have to figure out what to cut out or put on the back burner and decide to live with it. Life gives us lots of things we wouldn't choose, so get used to it. Eventually things will change as the kids grow up and become more self sufficient.
Maybe you are taking responsibility for many things that others could do. Do DH and kids do their share of home jobs? One time when I was sick with strep, I gave my (they were maybe 16 & 11) two boys a grocery list and my debit card and was amazed at the good job they did.
Maybe your kids or DH could fix meals now and then and do the clean up, even if it was something simple like sandwiches. You are going to have to find ways to cut back on your stress because it sounds like your body is giving out already.
Maybe you have to change your attitude about what is important when it comes to housework. The meals don't have to be a 5 course meal each time. The house doesn't really need to be cleaned from top to bottom every week. Or what if each person was responsible to keep clean 1 or 2 rooms in the house instead of you doing it all?
My Dh doesn't cook but appreciates my cooking. Even though I'm retired, he cleans up from the supper meal every night. He says it is only fair and it's how he keeps his hands clean. If the dishwasher has been run, he empties it before I get up in the morning.
What if you have a family meeting and let the others know how stressed out you are and ask if they have any ideas about how you could be relieved of some of the stress? I remember making a list one time of all the stuff I did around the house and sharing it with my oldest. Your family just don't realize how much you do to keep their lives running smoothly.
Don't forget that as the children get older, they must be taught to take on the responsibilities of the home in order to prepare them to take care of themselves and their homes eventually. Don't let them be one of those kids who go off to college and have no idea how to do laundry or cook. It doesn't matter if they are boys or girls. I had three boys and they all knew how to do it all. I made a step by step list of how to do laundry and framed it with a cheap black frame and hung it over the washer. They didn't have any excuse.
Anyway, hang in there Tinkster, some day this will all be a dim memory and you'll wish you had something to do. Just ask me how I know.