Is the Canadian Dollar expected to drop further in the next seven days?

It should be lower in the next week, unless it isn't.

Unless you need unusually large amounts of cash, you'd do better to use your credit card or withdraw at an ATM at the destination. On credit cards the commission would be 2.5%, on atm the same +depending on the plan fee for using foreign ATM. If you order cash , the commission starts at around 3% minimum at the banks.

I'm not a wizard, so I don't know

I would just do it as soon as it's convenient to do so i.e. I'm not travelling out of my way to pick up the cash. Even if you "lose" 2%, how much is it really effecting your travels.

Well apparently Gizmodo thinks it already has dropped by a factor of 1000:

"The Canadian government unveiled its 2018 budget on Tuesday, committing nearly $4 billion (or over $3 million USD) to a range of science programs over the next several years."
https://gizmodo.com/canadian-budget-ple ... 1823405476

The story has been up all day on their web site, and apparently no American readers noticed anything wrong.