1, That's a shame.
2, I screwed up.
3, I could kick myself, really.
4, All that for nothing.
5, I'm really disappointed with him.
6, I'm quiet dissatisfied with what he did.
7, I feel really sad.
8, I expected to be much better.
9, What a disappointment.
10, how disappointing.
11, it was a waste of effort.
12, what a fool I was.
13, You let me down.
14, My heart has been filled with grief.
15, Today just isn't my day.
16, It's not what I expected.
17, It a waste of time.
18, It can't be help.
19,What luck.