So you are saying you are a PR and have lived in Qatar for the last 5 years? Do you realize that PR's need to have lived in Canada 2 out of every 5 years to keep their PR status?
Aside from the potential problems with your PR status, it depends on what province you are in and where your drivers license is from. The provinces have exchange agreements with a handful of countries. If you don't have an exchange agreement but you have a foreign license and a translation of your license and something to prove how long you have been driving, they will let you take the exam to get a regular drivers license and after that you would need to find out about taking a test for an ambulance license. You may have to go to a school for that. You can find all the provinces drivers license info here:
Alberta: http://www.servicealberta.gov.ab.ca/drivers_licence.cfm#Exchanging_a_Non-Alberta_Operators_Licence
British Columbia: http://www.icbc.com/driver-licensing/moving-bc/licence-othercountry#Variables._frag_
Manitoba: http://www.mpi.mb.ca/English/dr_licensing/ForeignDL.html
New Brunswick: http://www.gnb.ca/0276/vehicle/english/faq-e.asp
Newfoundland and Labrador: http://www.gs.gov.nl.ca/gs/mr/dl-application.stm#new_res
Northwest Territories: http://www.dot.gov.nt.ca/_live/pages/wpPages/newDLandGIC.aspx
Nova Scotia: http://www.gov.ns.ca/snsmr/paal/rmv/paal269.asp
Nunavut: http://www.edt.gov.nu.ca/apps/authoring/dspPage.aspx?page=motor
Ontario: http://www.drivetest.ca/en/license/ExchangeReciprocal.aspx
Prince Edward Island: http://www.gov.pe.ca/infopei/index.php3?number=20138&lang=E
Quebec: http://www.saaq.qc.ca/en/driver_licence/exchange/index.php
Saskatchewan: http://www.sgi.sk.ca/sgi_pub/drivers_licences/new_residents.htm
Yukon: http://www.community.gov.yk.ca/motorvehicles/mvdrlic.html