I teach 5th grade on Chicago's West Side. I'll try to give you the pros and cons of what I do.
I'll give you the cons first.
1. Your 8 to 4 job is teaching. All the grading of papers, planning of lessons, and any other paper work is done on your own time. You can expect around an extra 3 or 4 hours a day of work beyond what you do in the classroom.
2. If you end up in a shitty school (be it administration, behavior of students or parents, money, or any other circumstance) you can feel as though you're running into a brick wall on a daily basis and can do nothing about it.
3. There will be some students and parents who will verbally abuse you daily. While I know this doesn't happen everywhere, there have been times where teachers have been assaulted and hospitalized by parents at my school because the child went home and accused the teacher of something.
4. The union will take your money whether you want their damn help or not.
5. The general public tends to think you're ruining our kids and politicians will blame you if your student with an IQ of 77 can't solve algebraic problems.
NOW, for the pros.
1. Once you bond with your students (which can take up to a month with some, even longer with others), there isn't a thing they won't do for you and not a thing you won't do for them.
2. Nothing can compare to knowing you helped an 11 year old read for the first time.
3. Having students come back to visit you years later because they miss you and you had that big an influence on them.
4. Hearing a parent say, "thank you for helping my child."
5. Knowing that you're taking a proactive role in their lives.
6. And having the vacations isn't bad, either.
As far as getting your certification, I'm not sure of the laws in Canada. My guess is that they may be somewhat similar to the U.S. I think Maleficent already provided a link for the requirements. A lot of states also offer alternative certification for people without education degrees who are wanting to switch careers.
Teaching is extremely stressful, but it's highly rewarding as well. Good luck with whatever you decide.