The important thing is that you already disclosed your prior substance abuse problem to your clinician, who then came up with a treatment plan, which included the risk that you may abuse the meds, keeping you on a low dose. Impulse control is a significant ADHD trait, where self medicating and an inability to set or keep to moderate limits are a real destructive force. What I mean is that you can allow yourself a bit of room to understand that you abusing your meds is as much a symptom of your neurodiverse impulsivity, as anything else, and one of the main reason to take the meds in the first place is to help reduce these symptoms.

One of the big issues with stimulant medications and ADHD, is that if the dose isn't strong enough, it has no helpful effect and so while starting you off small is one way to tackle the risk, if it's not strong enough to help with your symptoms, then you're going to feel the symptoms and there's a real risk of that inpulsivity to take more to increase the effect being present. This doesn't diminish your responsibility to being safe with your own medication but there needs to also be an empathetic reaction to it too, and a drive to help you reach the right place and support.

On a personal note, it can be easy to want to chase a euphoric feeling the meds give you, when you first start taking them and plenty of people feel that way, then question the efficacy of the meds when it doesn't, so don't blame yourself so much for that aspect. Short acting meds may be worse for this as they aren't going to cover remotely the time you need them to and keeping on top of medication timing's is remotely easy when you only have to take one long acting, rather than juggle multiple.