You should try a different shop and see if you can try to find a different brand that fits snugly. Each brand will have a different head shape, you just need to find the one that works for you. I like my hjc AC-x3, if full faced is the way you want to go, they also have open face motorcycle helmets you can try. One nice thing about motorcycle helmets is they tend to have less difference between sizes so it is easier to find a good fit.