Did you mean you learned English from video games in the 90’s? If so, I am impressed… I am not sure how comparable English is to Portuguese, but I do know English is not an easy language so anyone who can express themselves through what they learned on the playground/tv/video games is impressive.
Anyways, medication is not a universal experience. I personally felt a difference immediately but still needed help learning how to manage attention and focus. ADHD medication is an amazing resource but aren’t meant to be a magical cure all.
I know that sometimes finding the right medication is a trial and error process. I would vote for going back to therapy… you may need to adjust medication. Or maybe now that you are on the meds, you will be able to learn different work habits supported by the medication you are taking.
Good luck with everything and remember you aren’t alone in your experiences. Someone on here is bound to have some advice that you will identify with.