Oh my gosh, I think we have the same type of feet!!!!! Depending on the shoe, I can wear a 3 girls up to a 5 womens. My Timberlake winter boots are actually a boys size 2 LOL. I don't have the usual rounded heel either so my shoes usually don't have anything to grip (plus my heel is narrow but the top of my foot is wide). That's why I love these style Tevas. The heel strap has a cushion so my heel doesn't get a blister with the rubbing and the ankle strap is adjustable around so the sandals will actually stay on my feet and the top part of the sandal is also adjustable so I can fit to the wideness. It's literally the only pair that will work with my feet size and heel issue.I got horrible blisters on the bottoms of my feet from flip flops in the rain. That made me start wearing tennis shoes. The moleskin saved me that time. My feet are insanely small and I have ridiculously small heels so straps never work for me. I can wear a girls 3. I have been breaking in the teva flip flop style the past two days and they feel comfortable so far. I will be taking my Nikes in case but I know I will be so much cooler if I can stand the flip flops. I hate shoes... lol it is one of the things that depresses me about winter so bad. I would live in shorts, tanks and barefoot or flip flops all year if I could.