Help with playing

I think I may have lost my touch in this game . Is it only me? I've been losing a lot of games so i've been training low levels in lol (1-10). How does match making work? I was lvl 30 and with my lvl 5 friend , so why did we get to vs people lv 14 to 30 (14,16,22,23, and lvl 30) why?