It never rains but it pours
When one bad thing happens, it is usually followed by a series of other bad happenings.
وقتی یک اتفاق بد می افتد به دنبال آن مجموعه ای از اتفاقات بد پشت سر هم پیش می آیند.
I had a car accident in the morning, and then I arrived late at work. In my office, I faced my angry manager who needed one of my files. Unfortunately, I couldn't find it. Well, it never rains but it pours.