Hello Friend, Good that you are seeking a help here. Loss of motivation, dullness, lethargic approach etc are symptoms of emotional disturbance and you may call it as depression. It's not a major problem. As you know the root cause already , it more to put that extra conscious effort and mindset changes. You may need a guidance of counseling support to overcome by getting to know  your strengths and weaknesses and  identified a workable goals and solution . You can reach me online or reach out to any psychology counselor locally.

Knowing is knowing only....Doing only will bring in Results. How to do it,... For that answer, You can visit a psychologist or have an online consultation through this App itself.