When you are shopping or out you come in contact with other people or stuff touched by people each time we all take over the feelings and fibration of other people nothing wrong with that ofcourse because that is the thing that connects us all. 

In our DNA, energy field, skin, hair everywhere is energy of our verry own wich realeases when we feel a emotion this can go from happy to sadness or even anger, the moment we feel we release that energy and it will be everywhere mixed or even on the stuff we touched ( like a shopping car )

So  it happends that you feel a emotion you feel it is not yours, your innerself and mental body are trying to say that you need to clean yourself. Listen to that warning you can wash your hands or can take a shower or bath in de evening. There are a lot of simple things to clean yourself everyone has it's own way to do so. Do the method you like to do the most and wich one helps you.