Stimulants often increase anxiety. That could be the cause. If you’re taking an immediate release Adderall, it only lasts 4 hours and this might be the crash as it’s wearing off. Most people find that time-release medications wear off more gently. You might ask your doctor about trying that.
ADDitude Community Moderator, Parenting ADHD Trainer & Author, Mom to teen w/ ADHD, LDs, and autism