I use the calendar app and notes app, but what helps the most is having a planner book (a physical copy) to write down to dos and wants and future appointments, keep it somewhere important where you won't loss it like next to your meds or on your nightstand

If you are a nerd like me I suggest Do It Now. It gives me a renaissance/DND feel. You set a task reminder and when you complete said task it gives you these little gold coins. You can level up and get achievements. It's fun. Also, alarms even alarms for alarms. If I have to get ready for an appointment then I set a 15minute, 10 minute, 5 minute, and a 3 minute alarm. It resets my mind. May or may not work. Drink lots of water and intake less sugar. The sugar is okay but messes with my head and body. If I am consistent with water and protein I'm good to go. Watch yourself like around 2 you get tired maybe try and eat something small. If you understand your body managing it is easier.