I'm medium-large so I can't help you with clothing, sorry.
But one thing I'll say- you do need to get a thinner head covering that will not make your helmet ride so high up on your head. Thick knitted hats are no good- looking at your picture, your helmet is not sufficiently protecting your head.
Try a balaclava or a helmet liner or skullcap. It might be one item you should consider actually purchasing, for safety's sake.
Try looking at the head wear here at TE to get some ideas- click on the link at the top of this page that says "click to shop". There are some good sales going on right now at TE, too!