You Should Keep Your Private Life Totally Separate from Your Work.  

In my opinion, our private life and our work life should never be combined. I feel that one must be equally committed to one`s personal life and professional life as well. By this I mean that if due to any circumstances you are facing ups and downs in your personal activities, it should never reflect upon your work, and vice-versa. So, in order to work in a healthier workplace, and to remain committed to your work, you should keep your personal life far away from your workplace.
I can give an example to support my point of view. My close friend, [1] was very devoted to her work. On the other hand [2], in her private life she was a family-oriented person. But unfortunately, due to some differences with her husband, she started to experience a lot of stress not only at home, but also at her office. As a result, she was unable to work effectively at her office; neither could she concentrate on her work.
In conclusion, I want to say that you should not [3] mix your private life and your work life. This is because it can negatively influence on your private life or work life, as I have shown in the examples.

[1]  Better variant:  A close friend of mine was very.....

[2]  In this context, "сторона" should be translated by "hand".

[3]  The contraction "shouldn't" is a little too informal for your essay.