(take this with a grain of salt. I'm a bit tired while writing this)
>am I an infinite looser
That's tough to say. Probably, you are a bit of a loser, especially whenever you think pessimistically like that. I would also argue that most of us are losers at points in our lives, though, so maybe try not to let that get you down. Thinking like you are defeated, that's the moment you are defeated.
>That I'm a background character
If you feel like a background character, then that's probably because you are in a lot of situations. We are all a part of the same canvas here, and the vast, vast majority of us are going to be making up the background. There is nothing wrong with being part of the background, though, if you can learn to accept it and be happy, despite being in the background. What I'm saying is, you are expecting a lot from yourself. You said it yourself, the main reason you got pissed when you lost the card game was because you were sure that you could win. You put a lot of work into it, tried hard, but you weren't able to accept that you weren't capable of winning. Maybe it was chance that you lost. Maybe you are actually good at card games, and the reason you lost is that the planets aligned for your opponent. It's hard to say. There can be so many reasons why things aren't going your way at any particular time.
Most people if they fail at something go like this: "Well, you can't be good at everything. Maybe I'll find something else that I'm good at". This is a healthy attitude, I think, because if we had to accept every shortcoming as a failure, we would all be fairly miserable.
So, as far as advice goes, I'd say try not to let what the world does to you get inside your head. It's not always your fault when you mess up, you can be a victim of circumstance sometimes too, as long as you are able to recognize when you could have actively done something to improve your situation as well. If there's something that you want to be better at, then work hard, but don't build expectations if you can a