It sucks when your therapy stuff or whatever you want to call it interfers with your study. It's happening with me too.

I don't live in your country, so I don't know hoe it works there. It can also be different at each school.
I know at my school you can talk with a special person and make some kind of rules, like an adjusted schedule. You do need a note from your therapist.
Isn't there something written about it on your schools website? If not you should talk to a counseler or tutor at school.
And it's not choosing the easy way out. School is hard enough without dealing with all kind of other stuff.