I am so sorry about what happened to you, and the effect it has had on you, your life and your relationships. What happened was wrong, it was horrible and N should never have done what he did. You were not "stupid", and it was not your fault. I am so sorry that you felt that you could not tell anyone and that you thought you would not be believed. It is awful that your classmate defended him, that must have really hurt. I cannot imagine the pain and distress you must experience everyday.
I don't know if it is any consolation, but please know that you are not alone in what you are experiencing. What you have described is not uncommon after a traumatic experience where someone has violated your boundaries in such an invasive way. However, there is help available, and I know you may not be able to see it right now, but there is hope. Below I have listed a couple of the support services available, I would really encourage you to have a look at the resources and contact one of the support services if/when you feel up to it:
- Bravehearts (https://bravehearts.org.au/what-we-do/counselling-and-support/) have online resources plus a support line on 1800 272 831 (available 8:30am-4:30pm Monday to Friday)
- Headspace (https://headspace.org.au/eheadspace/) have a phoneline (1800 650 890) and you can also chat online too if you prefer
- Kids Helpline (if you are between age 12-25) is available 24/7 on 1800 55 1800 (https://kidshelpline.com.au/)
Another option if you feel comfortable, would be talking to your GP about what has been happening for you. They will likely be able to help you find an appropriate clinician/therapist who can help support you in processing what has happened and help you to heal. You deserve to feel comfortable in yourself, you deserve to feel safe around others, and you deserve the joy and fulfilment that relationships can bring - I really hope that you are able to get to a point where things can feel better.
Please do not hesitate to talk more if and when you feel up to it. We are here to listen and support you. Take care.