Watch your thoughts, if they are uplifting you really feel uplifted. If they are depressive, you feel pulled down into an abyss. Indeed you are but your mind. Feed it well with healthy thoughts of divine vibrations, with Naam smarana, chanting the Holy Name, so that you are not so easily afflicted by the virus of negativity that is all around you. When you are happy whoever comes to you feels the light of your happiness.