Depression? Me how to gain confident.

I am sfrng  from self underconfident and cmpring myslf wth othrs specially wth my ex gf who is studying MBBS. it was 2016 after i passed class 12 i decided for the NEET 2017 prprtion , there i met her in our institute  but i could,t clear NEET 2017and she got BDS. Then i thought to take another drop for 2018 and she did it too. We are preparing well suddenly their  had been a problem btw  us and brkup happened I was very overconfident during that timeand gradually i lost my track shifted my focus on brkup and what hapned  is that again i could,t clear NEET 2018 but she cracked MBBS st.I again took another drop thnkng now i am free from every thing my total focus should be on NEET preparation ,what hapnd  nxt  is i strted scrolling her profile on fb ,her new life new friends and she startwd avoiding me ..and i totally loose self confidant ,ego.(thinking i too a gd student) in my preparation and i failed in 2019.i am currently in physics(H). pls tell me how to gain confident.