J.S.
You need to relax. Take a hot bath, read something that's not child related, take a walk by yourself, go window shopping at the mall alone. If you haven't gotten your hair done in a while, go get pampered. Get a manicure.
If you can't get away from the kids for a while then put the kids in their rooms and make sure that they're safe where they are. Determine that their needs are met (fed, changed, clean, dry, safe) and lock yourself outside on the porch for a few minutes with a tall glass of something delicious with your favorite snack. Read while you're out there even if it's some gossip magazine. It's all right if the kids cry for a few minutes.
It happens. Anyone who tells you that your buttons won't be pushed has a bridge to sell.