Explain your reason for betting this size? Are you betting for value? Betting as a block bet? Betting as a bluff? My guess is that at the time you had no idea. Sure the range you give him after the fact makes it a value bet but while you were doing it you probably were like well... he might have a ten..... uh... 5 dollars is my favorite number... I'll bet 5!

Point is if you're betting for value then bet it bigger and fold to a shove. If you're scared of the K and the flush then check and evaluate what he does. This bet just looks like you have no idea wtf is going on and I would raise you 10000000% of the time if I was villain