What Causes Frequent Memory Loss?

My problem is fear of forgetting.Always i have a thought in the mind that i will forget this and that.These may be simple and routine things but my mind always have the fear of forgetting.Because of this my sleep is also disturbed.Infact i couldn't enjoy the present situation as preoccupied thoughts are always in my mind.What's the reason for this.Is this OCD?How to check sterotonin levels?What would be the correct treatment for my problem.Please help me.