I am not a successful person till now in this field but have given enough time to this preparation. I will suggest you 2-3 things to be done for self esteem, confidence or for that matter mental well being:-
1) please join a gym/ yoga/ some form ofphysical activityclasses or do at least 15 minutes of running on a daily basis or 20...25 minutes of exercise in home itself
2) practise awareness of the present moment or in some waymeditationwhere u can focus upon ur breathing- minm 15-20 minutes daily
3) be reckless in affirming urself in some form ofaffirmationseither in form of writing or reading out aloud ur goals for 100-200 times daily.
Hope these can make some changes to ur issues. Practise it for 2-4 weeks nd if there is no visible changes... leave it and try something else.
Practising more whether in terms of hours or writing tests will give you more confidence. If u r able to win here in tests series or u somehw abl to figure out that u r better than ur peers that may embolden u mentally
Please keep in mind that physical activity in these daily at a particular time in ur day for at least 5 days a week is the most important