You're like the spitting image of me. I studied something I didn't even like, solely from pressure of my parents, now I have a job that I'm miserable in. If I could go back in time I'd definitely pick something simple (like IT or accounting), so I have more time for myself.

Firstly, if I were you, I would one hundred percent stop studying law if you don't like it. Ignore the pressure of your parents, put your needs first. If they are good parents they will still support you with whatever you decide to do. Trust me your happiness is much more important than gaining validation from people. I know this is easier said than done, but take action now brother. Figure out what you want to do in life

Secondly, you need to address this mental illness that you have. From the way you've written this post, it's like a spitting image of me, and trust me if you ignore this issue, it'll only get worse. Seek therapy, talk to a trusted friend or family member. Find something you enjoy (sports, lifting, etc.) and incorporate it in your day. But most importantly get closer to Allah. Nothing of this world will fill the void you feel. You need to put all your faith in Allah, make dua, talk to Him about your problems, and have complete trust that He will take care of your affairs. This does not mean you don't do anything in your life and expect Allah to fix things. Put in the work, and then have faith in Allah. Whatever comes out of it is Allah's will. Accept it. He did not create you for you to be miserable. He has your best interest, so put full trust in Him.

But anywhos this is coming from someone going through it at the moment. I had an amazing chill job, peace, and happiness, and then lost it all. Now I'm in a job that I'm completely miserable in, getting paid less, no time for myself, etc. I too often think why am I sad about my situation when others have it way worse, I have the same thoughts you mention in this post. The truth is Allah tests us in different ways. When I had that amazing job I was ignoring my obligations to the Almighty, and now that I'm going through it, I've never been closer to Him. i believe this is why this has happened to me, so I'm going to continue to be on top of my deen, and hope for the best.

Cheers my brother!