Crests. Troughs. Troughs. Crests. These are just laws of a wave. A wave is a natural phenomenon.
Bad days follow good days.
And good days follow bad days.
These events are totally random.All you can do is not react on bad days. That is the only thing in your control. There are no factors which determine a day will be bad or good. There cannot be one thing which can turn a good day into a bad one, and definitely not a bad day into a good one.
Believing otherwise is irrational.
And the last thing you are is irrational.