Yeah, you should see about getting that checked out. If you're diagnosed or anything, see your school's financial aid department and tell them you've been diagnosed, are medicated and are looking to give it another shot. They should be like, "Okay, go through this appeal process, and we'll see about getting your aid extended and wiping your slate." They'd remove all failures from your transcript and give you a financial aid extension. At least that's how it works in the United States. But you're Canadian. It's an intuitive system though so I assume they'll do SOMETHING.

Anyways, yeah, tell your mom. And maybe don't omit the drugs unless you're CERTAIN they didn't cause any of the issues. It's sort of like a full disclosure sort of thing. You can ask the psychiatrist you see not to mention it to your mom and he won't. You aren't a minor iirc.