I am zero who literally was once a hero. Plz help plz

I(18/m) am studying mechanical engineering I don't even know why.I "was" simply scholar and obedient student.'Always' ranked 2nd or 3rd in kg to highschool,had a lovely gf.In short I was a hot shot.But in the end of highschool days I just got carried away.I became lazy,ignored studies,lost gf,got some bad friends and literally MESSED UP:( now I can't concentrate on study,no girlfriend, not close to even old friends.I just don't know what went wrong.My life was rolling smoothly and now I'm f*#ked up.And also lost self esteem. Now when my old friends are having great life in college/hostel ,I don't even have a true friend.Watched many motivational videos but they are no help. I literally don't eat at night in my hostel mess so that I won't have to face other students there.My self confidence is just gone.I look back and see how cool and happy I was in high school but now its all gone for forever I think. I have no energy to go on just like this.

Hero to Zero (soon to be hero again), Hey there! Thanks for sharing this online. There are not to many 18 year olds who are able to look at their life and evaluate it so well. You are clearly an intellectual and introspective person. I wish I could just restore your self-confidence, but we both know it is more difficult than just someone saying something nice! Here is a thought I had...maybe you could consider getting to the core of who you are, your identity. For me, that has helped. I stop and say, who am I? What is my purpose? and then what am I going to do about it. Does that make sense? For example. I am a child of XXXX family. That identify means my purpose is to honor my family and do my best in all things. Even deeper than that, I believe I'm a child of God and that my purpose is to love God and love my neighbor. When I get that clear in my head then I find it much easier to do what I have to do each day and it restores my confidence. (getting you back to hero again!) Again, not sure if that makes sense to you, but it has worked for me a few people I know... Good luck to you!

Thanks mate.You are right, I have to begin again amd concentrate on primary and simple things. It feels really great that someone completely unknown to me is helping me.Again I'm really thankful for ur advice.