Yes, it's definitely possible.
The first thing I would suggest to do is to write out a clear, well-organized timeline of events that explains the situation with your child, how the circumstances have changed, and why you believe your child should be returned to your custody now.
Also, if there is any relevant documentation or evidence make sure to hold on to it.
I have also found some resources that I hope will be useful for you. I suggest you consult as many as needed before making a decision about how to proceed.
1) Family Law Information Centre - Grand Prairie
780‑833‑4234
https://albertacourts.ca/resolution-and-court-administration-serv/family-justice-services/locations?loc=grande-prairie-court-house
2) Edmonton Community Legal Centre
780-702-1725
http://www.eclc.ca/contact-us.html
3) Calgary Legal Guidance
403-234-9266
http://clg.ab.ca/programs-services/family-law-program/
4) Student Legal Services of Edmonton
http://www.slsedmonton.com/family/sls-representation/
http://www.slsedmonton.com/contact/
All these resources provide free information over the phone, and can direct you to the correct forms to appeal the custody order. You may also be able to get a lawyer through one of these services.