Do yourself a favor and get a better pack. I have the same one you do and I thought it was great until I used it. Over a two day, 12 mile hike last summer one strap pulled off (not a shoulder strap) and a seam ripped out. These packs look like they are built well but they are not. My son now uses mine for paintball and I bought a Kelty.
Also, get a fishing scale from Walmart, <$10. I made that hike with a 50# load. Never again. My current pack weights 35# including a gallon of water.
Most importantly, get out and use your gear. It can be a real eye opener.