Thanks for the concern
its good you are a brilliant student and a topper always. that means you having capacity to come to that level, you just need will power and a bit of oriation towads your goal.try follow few tips:
Leave the work tension should to restricted to your working hours at office.
dont ever carry deparatment things back home.
your timing other than office should be for reading.
Start doing Meditation
daily for few mins this helps alot to stabilize the mind and increases concentration.
Go for fresh air walk early in the morning this refreshes your mind and body.
Always Remember that you can do it.
If you get free time at office dont waste ,keep a book and try to read.
Have confidence on your self.go ahead surely you will reach your goal.
all the best