Yes, it might be extremely difficult at first to force yourself to focus on something. I was "diagnosed" with "ADHD" as a "kid" (im only 13)
I sometimes have troubles sleeping at night, too, because I keep myself awake because of thinking. A lot of people do. If it happens every single night with you, guess what, I think you have a sleeping disorder. This sleeping disorder probably contributes a lot to all of your "ADD" symptoms.
If you don't have a sleeping disorder, you need to work on self control. Force yourself to focus. It will be hard at first, but these things do get easier with time.
Tell yourself you can do it, show yourself you can do it, you'll be fine.
Don't start paying for "medicine" you don't "need."
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