I am taking Vyvanse for ADHD. I was on 40mg for a few months but recently I was bumped up to 60mg as I was struggling with inattentiveness and starting to feel fatigued and low in energy later in the day and early evening. I've only been on the 60mg a few days and its working to mitigate this but I think its causing insomnia as it takes me two to three hours before I can fall asleep. Is this usually a temporary side effect as my body adjusts?