1.
If you say that someone had some ~, or that a situation was ~ on them, you mean that something bad happened to them and you are implying that it was not their fault. (INFORMAL)
We had a bit of ~ this season...
= bad luck
N-UNCOUNT
2.
If someone says that a bad situation affecting you is just your ~, they do not care about it or think you should be helped, often because they think it is your fault. (INFORMAL)
The shop assistants didn’t really want to discuss the matter, saying it was just my ~.
= tough luck
N-UNCOUNT: poss N
3.
You can say ‘~’ to someone to show that you are sorry they have not got or done something that they had wanted to get or do. (INFORMAL)
Hard luck, chaps, but don’t despair too much.
= tough luck
CONVENTION feelings