My biggest advice to you is one that you might not immediately like, but please, give it a thought:
Don't look for a job yet.
Go on with your education. Go to university. Learn about agriculture, or about ethics, about the climate, or just about anything you're interested in!
If you think you need to work in order to study, apply for scholarships first. Ask your family.
If everything else fails, work something alongside your studies. It doesn't matter so much what you do, just avoid fast food, and you'll find plenty of opportunities. Look at all the vegetarian restaurants and shops there are in Ottawa. They might have a job for you.
Why all that?
Because you can do so much more with your life than just avoiding work at McDonalds. There are jobs for vegans out there that can change the world, and you can get one of them eventually.
But most probably not from where you are right now. You'll have to work your way up in order to make a change. Complete and extend your education. Build what's called "career capital", which means, skills and such that will help you do a really good job.
Have a look at this short article about where to start to work against factory farming. In order to do something for the animals, research is needed, heck, good politicians are needed.
You're vegan at 15, I'm impressed. It took me nearly double as long as it took you. You're probably strong willed, and you can probably go a long way, and make a big difference.