i dunno, i'm not that high rated but opponents who have a high rating make me look absolutely pathetic, but then my games look like masterpieces against opponents who are lower rated. It's sort of a universal thing.
You make mistakes when playing higher rated players. It's okay. You're human. I'd play people close to your own rating at first--then play slightly better players. The main thing, in your case, is to believe in yourself. We all make mistakes and blunders at times. I often have trouble with this, so I understand a little bit. Sure, you will have to do more than believe in yourself (ultimately) if you want to win more games, but don't beat yourself up for losing. Nothing good can come of this.
I'd find a better player with whom to practice what you already know. You can also learn some new techniques. You might not need a chess teacher. There are a lots of good players on this site. Ask to play an unrated game with someone. Ask questions while playing practice games, if it is appropriate. When you are ready, you can play "real games" (possibly unrated) with a friendly person.