As i said majority of cases with gap of more than 2 years even with a valid reason don't get visa. Although sometimes cases with 3 years are still excepted by the embassy. I am saying this as i have been working in this area since 5 years.
you have a long study gap that is of 5 years and canada accepts of only 2 years max with relevant work exerience, only in rare cases they grant visa for people with more than 2 years gap,
hope you find it useful.