I'm just disappointed. 我只是失望。

I was looking forward to it.  我期待它。

It's a shame that we couldn't go.  我们不能去是一个遗憾。

It's not what I expected. 那不是我所期望的。

Words and phrases

disappointed失望的, expecting期望, shame令人惋惜的事, paycheck薪水, mad发怒的