I’m a college student and I had the same experience. I talked to my psychiatrist and she said there’s a new form of Adderall that’s an extended extended release, and there’s a discount card to make it cost only $3. The only downside is that because it’s brand new, there’s only name brand so insurance won’t cover, and it’s h*ll and a half to get my meds filled on time because the pharmacy won’t accept refills until 2 days before or the day of last dose. Hopefully an off-brand will become available soon, because this med has been really helping me stay on top of my game until I wind down to go to bed at night.
I would talk to your psychiatrist or med prescriber about options. I was also offered a “booster” which is like a very small immediate release that you take right before the extended release wears off. It doesn’t work for everyone (I would often forget to take it and suffer the consequences) but there are other options out there. It’s really tough, especially for school age children and college students, when it comes to finding med combos that work for us. Just keep your child in on the conversation, because being able to identify when your own meds are wearing off can be a huge help. Then you can start to use “Wise Mind” (https://www.dbtselfhelp.com/html/wise_mind.html) to identify what are good actions, instead of letting your ADHD run rampant.
Hope this was helpful!! Good luck! 🙂