Dear M.U.M.
I won't call you MessUp because you aren't messed up - you're just struggling with things a bit at the moment, and that can change. Anyway, your nickname spells MUM to me, and that's how your DCs see you too. You are obviously holding things together for their sake, and you can be proud of yourself for that.
I've been lurking on your thread since you first posted, and thinking about you. All I can say is that there are plenty of stories, especially here, of mothers who have been through what you're going through and coming out the other side, glad that they didn't give in to the urges, not only for their children's sakes but so that they could enjoy the future which for you is just around the corner, out of sight at the moment, but it's there.
Lots of people here have been helped by calling or texting the Samaritans. Could that work for you? Would you get some satisfaction from sorting out those school name tapes? Try to do something that will make you feel good about yourself, however small it might seem. More importantly, get a good night's sleep. Have you been taught the 7/11 breathing technique? Count to 7 for the in-breath, 11 as you exhale. This will calm you down, I promise, and help you to get to sleep. Tomorrow is another day, a fresh start, and you will be OK.
You are not alone. i'm thinking of you and will check in tomorrow x