I agree, I like Daniela but that was painful to watch.
I think she really has problems. I don't have a way to know but it seems to me she is under a huge preasure, from her coach, her family, the media or whoever it is.
I really don't like her coach, during practices, every time Daniela missed a shot he would criticize her, but not constructive criticism, just putting her down. She would tell you that she hit the wrong shot but wouldn't tell her what the right shot was supposed to be. Daniela looked like afraid of missing or doing something wrong, and remember how he leaves the court if she isn't playing well.
Daniela is very emotional, probably one of the most emotional players I've seen and as Tracy Austin said, with that attitude she is going nowhere, she needs to learn to control her emotions and I don't think her coach is helping her, quite the opposite (I think he is the root of the problem).
I also believe her weight problem is tied to this.
I remember last year in Montreal, when she was losing to Amelie easily and somehow managed to come back, she couldn't help but smile, not a normal smile, it was really her emotions flowing, like she couldn't control it, the same happens with the crying.
She wasn't crying because she was afraid of losing, she was crying because she was missing, and she is not allowed to miss, I think that's what her coach has lead her to think.
I really believe she needs time off, forget about the rankings, get a psychologist and get rid of that coach.