if you notice the article it only talks about oil and gas sector. So, yes the oil and gas sector is facing problems. Close to 20,000 jobs were lost. But its only for that domain/sector. Domains like IT, Manufacturing, aerospace, agriculture processing are as good as normal. So right now oil sector is facing issues because of the fall in oil prices. Middle East is the largest supplier of oil across the world. When the prices fell all oil sector organisations faced a tough time. This has impacted only Alberta province, there are only oil industries in this province. SO this province is heading towards a partial recession until oil prices stabilize.
canadian economy is not completely dependent on oil, TOronto, Vancouver, Montreal have several jobs in automobiles, aerospace, manufacturing, IT domains. You need not worry about jobs.
To detail more: From what i have read on articles regarding Alberta's recession. There are some people who have proposed that there is a conspiracy theory behind the fall. The theory is:
Alberta is so rich in oil that it is a great source for USA. Being its neighbor USA wants to conquer or take over Alberta province from Canada jsut like Alaska. Hence the artificial recession has been created by USA. But this is still a conspiracy theory, no official moves have been made by USA to take over. USA's economy depends on oil so its up to you on how you see this.
From what i know all other domains like manufacturing, construction, IT, Finance all domains are stable and running good.
Bottom line: Things will change, Oil sector is only facing recession so choose your course, province accordingly.