Hello and Welcome to ‘Ask A Doctor’ service.
I have reviewed your query and here is my advice.
Is there any other symptom present along with loss of concentration like feeling low all the time, loss of interest in previous pleasurable activity, crying spells, feeling lonely, change in appetite and sleep, low in energy, confidence, hopeless, helpless, worthless feeling or suicidal ideas? Few of them or all can be present at a time in
depression. If yes you need to seek treatment for the same from a
psychiatrist. If loss of concentration is the only symptom you are facing at present then you can increase your concentration by taking interval of fixed period after working for time period which is increased gradually. For example, work for 10 min then take a gap for 3 min and then again work for 10 min. On next day increase it to 15 min but keep the break time same. This will help you in improving your concentration.
Hope I have answered your query.
Let me know if I can assist you further.