Obsession, possessiveness, mood change.

A mix of obsessions and unwanted thoughts at certain situations related to certain individual. May It is obsessive compulsive disorder. But it never led me to any compulsive actions except my mood change and a total breakdown of my normal thinking. Not able to focus on work or anything else. May be a kind of possessiveness related mental shut down. I know it is wrong but can't stop thinking about it. I feel totally unsettled and broken. Seeing someone in a certain way, their certain kind of interaction with others triggers this breakdown. A bunch of emotions chokes my mind. Impossible to come out and work normally. The thought follows everywhere. Sometimes need to cry for some solace. Need help to overcome this.