Carrie breathe. You are not alone. I just don’t invite people over. For the Easter Egg hunt just try to do better next year. Take Should Have and Would Have out of your vocabulary. And another book for a disorganized person is just one more item to have piled in the mess.
For kindergarten child you need to put all the items in the backpack. As he is now a big person he can be responsible for that. If the teacher said to make sure he had extra runners and they can’t be kept in class you can make sure he finds these and starts to keep them packed and ready to go. Then you are at least trying to train the kids to not follow in your footsteps. And a kindergarten child can help supervise the picking up at the end of playtime. They love to be the boss of the younger ones and this is a natural inclination to be the teacher. Use it to your advantage. Maybe DH can be responsible for reading the school newsletter and relaying the important parts to you. Or ask that you only get the news about the kindergarten class and forget what is going on in every other class. Then any important announcements are there. As for homework, I found that the best time to do this was immediately following school when they are still in work mode. So sit this child down for the 10 minutes or so and get him to complete whatever they sent home. This is good practice for later. If they are at a sitter after school even better. Then you can designate someone else to make sure work is completed and in the backpack for the next day. A communication book is also a good solution to keep you in touch with what is going on at school. The teacher fills in a note and you reply if needed. They can also give you a list of things that the child needs and then you can send them to fill up the pack when you get home.
As for everything else that is overwhelming you, stop. Breathe. Then pick one thing everyday and just see what you can accomplish. It doesn’t have to be for an extended period of time. Just the first thing that catches your attention. And then get the kids in the act so that they know that they are not mess making ornaments. I know tasks are easier without them but it is important for them to know that when there is a mess they are part of the solution. 