I think it is due to less attention and concentration when doing things or doing any work.But question is why u less attentive?is there any problem in ur mind which will block u to do the work properly,or any other causes.
Many causes are there like over stress,worse memories, sexual assault, harassment, overmedication, etc.
Immediately consult psychologist online or offline and evaluate ur proper causes and then u can properly know the exact way to deal with it.
Health Tips
Regular exercises.
Relaxation exercises.
Avoi too much social media.
Share ur thoughts witg parents or friends.
Try to narrate ur inner emotions to any constructive form like-painting, dancing,singing, writing etc.
Feel free to Contact.....