You appear to be quite distressed which is distracting you. It is likely your forgetfulness and lack of attention can be attributed to some stressor. Loss of interest, decreased concentration and attention, feeling low and disturbed sleep or appetite are some of the signs of depression. Consult a psychiatrist who will assess you in detail. If you are feeling suicidal or hopeless, seek professional help immediately.

Is  that condition  always there  Or only with specific people and specific situations? If it is so,  I think know you are suffering from conditioning your mind. A CBT from a Psychologist would be beneficial to recondition your beliefs and behaviours

Dear friend, In todays mechanical world these symptoms have become quiet common with the youngsters. Follow one or more of the below given tips for improvement. 1. Avoid taking non vegetarian foods after 5 pm 2. Increase the intake of water 3. Go for regular sports/walking 4. Sleep properly for minimum 8 hours daily 5. Learn simple relaxation technique These will help you improve in your condition.