Congratulations on having clarity when it comes to diagnosis! I hope it's helpful to have a name for the beast.

What you are describing sounds like a pretty typical response to stimulants for someone with ADHD - you feel calmer rather than more wired. The silence can be deafening at first... I remember sitting there thinking "what now?" I'm not sure how long it took me to get used to it - I remember loving the feeling of inner calm almost immediately. I felt way more focused, and like I could prioritize and order things in my head, which I cannot do without meds. I could "map out" my entire day in my head, which was unheard of before.

Keep in mind that this dose may not be a therapeutic dose for you (that's a dose that takes away symptoms to the point where they are completely gone or barely noticeable), and you may need to go up or even change meds. I just want you to have realistic expectations that the first med you try may not be exactly right. Here's hoping that you find what works fast!