If you have I-Phones, use the family calendar option and put all appointments, after school activities, hobbies, birthdays, holidays etc in there so your DP/DH can see them too. Train them to use it/add entries too! Check each morning at breakfast time & co-ordinate which parent is doing what eg after school pick ups, dentist appointments etc.
If you get school emails, check for these daily & see if they’re relevant for your kids & put in the shared phone family calendar eg dress down day, exams etc I also have a big family calendar pinned up in the kitchen with school holidays, birthdays on which we can glance at easily.
How old are the kids, can they help in any small ways, eg putting clean underwear/socks into a named basket before putting into each person’s drawers?
Try and have at least a couple of easy meals in the freezer for busy days.
Keep spare birthday cards in the house, you can add a voucher or bit of cash quickly for any “forgotten” birthday.
Make time for yourself, sounds obvious but get enough sleep, try a quick five minute mindfulness, I found a great one on YouTube from the Priory - Centring Breathing Meditation with April Kerslake (6 minutes) Hope the link works!
Don’t forget that no one is perfect and to ask for help if you need it, you sound like you’re doing great x