Just my luck is said bitterly when something goes wrong for you again. Just my luck, the one day I forgot the umbrella.
It claims a pattern rather than an accident, which is what makes it funny and a little self-pitying. It is said after the event and never before.
1phrasejust my luckSaid bitterly when something goes wrong for you again.
“The last train was cancelled, which is just my luck.”
just my luck is a phrase.
Practised in Small Talk & Everyday Phrases