Carry-on Luggage

I know that I expect to do some shopping on my upcoming trip (one week away), so I wanted to take my carry-on luggage that has lots of space. It is the maximum size for carry-on luggage for Air Canada. However, it was not practical to take luggage and a carry-on that both have to be pulled.

I have decided to use my knapsack as my carry-on. I just hope I don't put my back out on the trip. I always take too much when I travel. Either my luggage or my carry-on are too heavy. I wish I could travel with one bag. That would make life so much simpler.