Pal two weeks are nothing. To put it simple, I played FIFA from version 98, and finally in 2004 I somewhat was able to defeat other guys, then in 2008 I was something like a okay player, in 2010 I was making fun in legendary mode, still I am BAD gamer, but yeah I did defeat some heavy weight guys.
Besides, if I were you I would not give a damn that I am losing. That person you are playing against, is he playing these genre for longer than yours? If he is, if he plays it or practice it often then he should win imo. I had this same irritation some weeks ago while playing with a friend, then I saw him playing with another person, and quite honestly I was happy that he defeated me repeatedly, he is just a better player than me, of course, and I am talking about FIFA 13 here.
On the game, well, till now, FIFA 10 is my limitation. I couldn't understand how on earth to defend in FIFA 13 (same for previous two versions, it's like a wonder to me. So I gave up.