When I first got my medium PS1, it seemed small as well, but it "bottomed out" as I say, and appears a tad larger now that I've worn it in. I think it's a perfectly proportioned bag. I'm 5'11 for reference. My mom, who is maybe 5'7, has a large, and I just adore it on her. I like big bags on anyone, small or tall. It looks great on you, and if you love bigger bags, stick with it. You love them for a reason, and it might better suit your needs. I do love the medium on you though, it "fits" you perfectly, and doesn't appear small at all. Maybe that can be your next purchase!