Taking adhd medication after abusing stims

I have used a lot of different stimulants (research chemicals) in the past and I actually was addicted to them. It was awful, I've done many drugs but only have been addicted on stims and weed. I got clean and haven't taken any drugs except weed for a year now. Just a week ago I got diagnosed with adhd and got a subscription for concerta (methylphenidate). I told my doctor that I was afraid of them because of my past relationship with drugs but he calmed me down saying they are not party drugs so I wouldn't get addicted and it's unlikely I abuse them. I feel confident that I can handle myself a lot better now but I'm still a little afraid that in a moment of weakness in the future I might fuck it up. Any similar experiences or any recommendations? What do you think about it?