So I handed in a medical form for a deferred exam. The lady told me that I should see a DEF beside my course on my grade report (it said 0 initially) by the end of the week. It still shows as a 0 - Does this mean my deferral wasn't approved?

It took about 2 weeks for me to get it approved. It says DEF in my grade report and I got an email from the eng. office about it being approved too.

I would email your academic advisor right away. It might have gotten rejected.