You are not alone, please talk about how you are feeling to a trusted adult. I know that's not always easy, but the more we try the easier it will get. Please have a look at these helpful sites which may help to support your mental health and well-being:
https://www.studentsagainstdepression.org/
https://www.youngminds.org.uk/young-person/my-feelings/
https://www.kooth.com/
https://www.childline.org.uk/
Student Mental Wellbeing toolkit