Oooh, I really understand and sympathize.
I've had talks with with friends who are coaches about how boys are coached vs. how girls are coached. Most coaches were men, and were coached by yelly, you're doing that wrong types, and yet that worked for them. They lived for that one pat on the back or the one "not bad," as opposed to the countless "what the hell were you thinking out there?!!"s that they got.
So, that's default mode for a lot of male coaches. (Some female ones too.)
Meanwhile, girls especially tend to do better with the carrot AND the stick. That was good, you need to work on this.
A friend had the exact and I mean exact situation going on with her daughter, who plays goalie for our soccer team. The dad is a coach, and he's a yeller. Daughter was getting upset and spiraling downward instead of getting better. The mom said she'd pay her a dollar for every stopped goal, and that totally worked.
By the way, another exact parallel, and forgive me if I'm overstepping here, but this coach/dad was laid off a while ago and I think that has an affect on his coaching. I think his self-worth gets caught up in it a bit -- it's not just coaching and getting the best performances out of the girls, it's reflecting on him, ya know? If his daughter does well, he's a good coach, and since he's not working (and feels terrible about it), that's more important to him than usual.
For sozlet, when she's lagging, I tend to give detailed praise on what she did well -- not just "good game" but "that pass to Anna was perfectly executed" or "I was impressed with your speed when everyone was trying to get to the ball [at one specific point]," stuff like that. It seems to get her back on an even keel when she's had a less-than-stellar game (there's always SOMETHING to praise) and also she tends to do more of that good thing next game.