I'm sorry that sucks . I know the feeling. I applied four years ago to U of T (a year after my undergrad) and didn't get in. When I applied the first time I also had very little experience in the field (worked occasionally as a respite worker, and volunteered at a residential program for at-risk youth). I did my undergrad at UBC in psychology. And had an 80% average in my last year.
Since getting rejected I have worked 2 years at a youth detox as a youth worker. I am currently working as a youth outreach worker (fulltime) and at a safe house for Aboriginal youth (casually). I also took a year off to travel. At the time of my application I had about 5500 hours of social services experience.
I have heard that in order to be accepted into an MSW program at U of T (and probably most MSW programs) they want you to have considerable experience doing similar work to social work already...or else they recommend you to do your BSW first. This is why very few people get in right after their undergrad.
If you are having trouble finding paid work experience in the field I have heard volunteering at a crisis line looks very good on an application. After gaining crisis line experience you should be able to find paid relevant work as well. Also, most MSW programs in Canada value work experience working with marginalized groups.
Additionally, I took a social work class at UBC after my undergrad to show my interest and demonstrate I could achieve a good grade in a university level social work class. You can also take workshops or obtain certificates such as ASIST suicide training or Trauma Informed training to boost your resume and experience. Not sure how or if this impacted me getting accepted this time but it can't hurt.
Best of luck to you