Up the creek (without a paddle) impolite informal slang
To be in a difficult situation without any possible solution
This morning I overslept and couldn't get to school on time for the final exam, so now I'm really up the creek without a paddle.
My bike just got robbed yesterday, I'm really up the creek right now.
To punish someone or something harshly
When you experience extreme and undesirable situations, it is probably essential to take extreme actions
Once something has been done, you can do nothing but face the consequences.
This phrase is a military slang from the 20th century. It refers to being lost, as in when on patrol, etc., like someone in a canoe being stranded in a river with no way to paddle.