Dear student,
Ask yourself
Whether your marks will really define who you are
There are lot of people who don't even get education and crave for it .There are lot of them who are repeating over and over to pass all the subjects and then there's you who has successfully passed 12th and is sad because you didn't score well in just one subject.
It doesn't matter in the end how much you score
The only thing that matters is what you wanna be how big your goal is and how you can achieve them
If you really workhard to achieve your goals no matter what you are now one day you'll be able to achieve it
Good luck mate life's very short you can't just cry on to things which happened in your past
You can definitely change your future .
All the best .