due to the fact that youre under 18 i think. your parents woukd have to sign off on care, i'm not entirely sure on that fact however
without knowing your issues its hard to say what would help, and im not going to ask your issues either. thats your concern, you have no obligation to tell them to a stranger on the internet
CAMHS (child and adolescent mental health support) are the general psychological support provided across the uk through the NHS, though this does mean wait times can be very long
there are also individual mental health services one can apply to (self referral), though depending on your county these may have different rules and regulations for eligibility. i got my link to my local service looking up CBT on the NHS website, that may be a good place to start just to get to your local directory
other than that there are services like child line, mind, the samaritans, and numerous others
if you feel you are a danger to yourself or others please call the national suicide prevention hotline or the appropriate emergency services to get in the moment support
otherwise all i can suggest is speaking to your school about getting some form of support, but telling them youd be uncomfortable with your parents knowing. you may be able to frame it as an afterschool club
dont assume medication will fix the issue you have too. all it does is level the playing field so you have a good enough chance at getting back on your feet
wishing you the best