Pitching control

I'm a 14yo and sometimes on the mound I tend to lose focus and start throwing balls. I notice that when I try to throw just to get a strike, I drift it high and inside on the batter. Then I try to correct myself and throw low and outside and there it goes as a past ball. Anybody know what might cause the ball to drift high or high and inside to a hitter? I was thinking it's probably my mechanics, but what in my mechanics is making that happen. Thanks in advance.

Keeler