Supposed to be a 6

I went for a jog on Sunday. I set out to do a six mile loop. I was wearing my 5 fingers but on an asphalt path. I think I combined too many unknown variable and made it too much for me. At about mile 3 I took my shoes off because they were blistering my feet. at about 4-4.5 I had to break down and walk. Bummer.