If you are worried about being let go on the spot without pay, you should first research to make sure you know your rights as per your provincial labour regulations.
Here's BC's
https://www.labour.gov.bc.ca/esb/fac...ermination.pdf
Note, however, if you quit, you are not entitled to any additional compensation. Example, "I quit, right now, today." So be clear that you are not quitting as of March 17th, but that you are giving your 2 weeks' notice to resign effective March 31 (or March 28, if that's your intention) as your last date of employment. And date the letter under your signature as March 17.
So if they choose to terminate you ahead of your resignation, they will have to follow the provincial labour regulations (notice period, or corresponding compensation as per your tenure there).