good luck, withdrawals shouldn't last too long, don't cling to the notion that you're completely incapable without the medication.

You will probably have a tougher time, more akin to before you started the meds, that's a given assuming you have genuine symptoms, but, with any luck the time you've spent on may have helped you engrain some better habits towards achievement that you can more effectively engage in without being too blindsighted by those symptoms.

I do notice when I take breaks myself that it's significantly easier to do stuff I couldn't manage before simply because I practiced while on the meds, but not everything.

As a sidenote: Don't stress too much, You're 16, you're young, you got plenty of time to work things out for yourself, enjoy your life for a while, don't put too much pressure on this time of your life in the sense of 'everything rides on this', just kick ass at what you do, if you feel the need to go back on stims at some point that's perfectly okay, it doesn't make you a failure, so should a time like that arise in your life later down the line, don't beat yourself up about it