Rojita,
You should speak to a Canadian lawyer. Canadian law is different from Mexican law, and there is a good chance that your husband must still support you.
Hola Rojita
In first place you shouldn't write any papers without a lawyer as a backup; anyway done is done.
Now, I can see that you already have your PR, so you may contact with an Organization for help, there are a lot of them in Canada
Suerte!!
Eduardo