Firstly, it is obviously very important to use phrases that are suitable for the level of trauma(创伤;伤害) involved.
1)You might describe someone as down in the dumps or down in the mouth if, for instance, they did badly in a job interview or failed an exam.
若是考试不及格或是面试时表现不好，那时的心情可以用down in the dumps或down in the mouth来描述，表示“沮丧的;闷闷不乐的”。
Similarly, the phrase out of sorts is used mainly for someone who is usually cheerful, but simply seems a bit glum at the moment.
同样地，如果某人通常都很开心，而此刻有点glum(心情不佳的)，我们可以用out of sorts(闷闷不乐的)来表达。
2)However, if the sadness is caused by something serious like a bereavement(丧失亲友), those phrases would sound too trivial.
For that kind of situation, we could say that they are broken-hearted or completely grief-stricken. In British English, we talk about people being knocked sideways or knocked for six in order to emphasize their shock and pain. If someone is extremely upset about something, we can say they have taken it hard.
这种情况，一般用broken-hearted或grief-stricken来表达，意思为“悲痛不已的”。在英式英语里，常用be knocked sideways或knocked for six来表达。如果伤心程度极大的话，可以用take it hard来表达。
3)An informal but emphatic phrase, which seems to have become much more common recently, is to say that someone is in bits. Strangely enough, it doesn't have any negative connotation, whereas if you say that someone has gone/fallen to pieces or fallen apart, it can sound slightly judgmental, as if they are failing to cope with what has happened.
最近比较常见的口语化的表达是be in bits，这个短语更具强调效果。这个短语没有任何消极色彩。但是，如果使用go/fall to pieces或者fall apart，听上去偏消极，暗指某人无能应对所发生的事情。
4)A continuing bad situation can get you down or cast a shadow over everything, while if you feel as if you are carrying sadness inside you, you might describe yourself as having a heavy heart. We often talk about doing something with a heavy heart when we are forced into an action that makes us sad.
如果糟糕的情况一直持续的话，可以用get sb. down或cast a shadow over来表达，含义为“蒙上阴影”。而如果内心一直觉得伤心的话，可以用have a heavy heart来表达，也可以说do something with a heavy heart。
5)If something makes you feel as though you want to cry, we say that it brings a lump to your throat, and if you well up, tears come into your eyes, and you might even burst into tears.
如果某事令人伤心欲哭，则可以用bring a lump to one's throat。如果用well up，含义为“满含泪水”;此时，有可能会burst into tears(嚎啕大哭)。
However, as sad as life can be, we don't like people who mope around or wallow in their sadness, as if they are enjoying it. If we are brave (or rude) enough, we might ask them to pull themselves together.
然而，有人也会沉湎于悲伤之中，此时我们可以用mope around或wallow in one's sadness来表达(我们可能不太喜欢这类人)。如果我们要宽慰他们，则可以鼓励他们pull themselves together。
6)And lastly, in case this post has left you feeling dejected, forlorn, glum, miserable or wretched – look out for my next post which will be all about happiness!