This sounds like tilting. Competitive players of any game or sport tend to play with a certain level of concentration, an ability to have a high awareness of the game. Basically "being in the zone". That awareness can be interrupted by a misplay or a bad luck streak, wherein the player gets frustrated and begins to lose his/her concentration and thus performs even worse. It can often continue in a downward spiral, such as what I think is happening in your case (bad luck -> aware of failure -> frustration -> perform worse -> aware of more failure -> more frustration -> perform even worse -> etc).
So in order to regain your concentration, you need to stop thinking about those recent blips. Nothing substantial has changed here, you still possess the ability to play TCG as always. If it helps, remember your past victories and how far you have come as a player for motivation. And remember that ultimately you do not play to win-- you play for fun and for happiness. If you are getting highly frustrated for losing, then I think you are playing the game for the wrong reasons and are letting it become more than a hobby, in which case I think it's a good idea to take a short break.
And look in detail as to why you lost-- Some bad decisions, or a deck unsuitable for the metagame?