Confused With Empathetic Emotions

Being an empathetic person is not all that it seems to be. It can be useful at times but more often seems to be annoying. Going out to do regular things - such as shopping, going to grab a coffee from Tim Horton's, or just trying to meet someone new to possibly become friends with - can be complicated and draining. I am 20 and I really enjoy being outside but going out means walking by people with different emotions. It especially becomes difficult during holidays such as Christmas or Easter when people are quite obviously frustrated, worried, sad, etc. I would love to know if their is a way to control it. A way to use it when I feel the need and to shut it off when I just want to be able to enjoy my time outdoors. I do not want to seem like someone with a personality disorder when I am trying to meet some new friends and My mood changes due to another person with strong emotions. I am usually a very happy and easy going person but the emotions of others can put me in a depression that can last from anywhere between overnight or up to a week. I have tried to distract myself from the walls of emotions by reading a book or listening to some of my favourite music, but it does not work as well as I would like/need it to. Though being an empathetic person does have some good points such as helps me know when to comfort someone close to me or when to make someone laugh, it can be emotionally (and sometimes physically) draining while in large crowds. So I would like to know if there may be a way to control it? To use it when I need it and to shut it down when I do not need it?