How To Not Be Affected By Something Bad

I'm relatively a positive person and usually pretty good at
not being influenced by people's bad behaviour,
but when I get slight series of misfortunes,
which are not serious such as continuous lack of sleep or bad health and so on,
I tend to take others' bad moods in a bad way.
Do you know what I mean?
It has probably been a long time habit of mine to absorb emotions/moods of those around me.

How would you keep your mind calm after when you accidentally
meet disagreeable or moody people or just something bad?

First, I thought the best way is to get me busy not to give the time myself
to think something like this, but this doesn't seem to work, and I may be more tired.
I need some time to practice not to take others' mood.