What happened to my sex life?

i think i have forgotten how to have sex..see for the last 2 years i just laid on the bottom and let him do the job. i used to be all about sex, i used to be a "freak" you could say. i knew how to turn him on and how to make him enjoy it, but now when i go to get on top, i'm confused like i've never done it before and i guess you could say a little embarrassed. we have been together for 5 years, but no i haven't lost interest in having sex with him...i actually ask for it all the time, but i just don't know what to do while doing it. it might be because he used to turn me down when i would try to turn him on, like kissing on his neck or something and he'd say something like "that tickles" and shrug me off, or say that he was too tired or in pain (because of his legs being broken in a wreck in 08 and it still bothers him). i used to dress up for him and everything, now i don't know what he likes or how to turn him on...what can i do to fix this? i'm too embarrassed to try new things anymore...like i said we've been together for 5 years but we're only 21 and 22 and we still enjoy sex so thats not the problem, and we're getting married in 2 months and i'd like for our wedding night to be memorable if you know what i mean! any advice is greatly appreciated and thanks in advance!