I had a hard time in high school as well. One thing I regret is that I kept my struggles mostly to myself and didn't know how to ask for the help that I really needed. If I had I might have been able to avoid some of the struggles I went through during and after high school. If I had just had the courage to ask for the help that I needed, I really could have made things much better for myself. So if I were to give you any advice it would be that if you need help, don't wait, ask for it now.
If you have a supportive family, involve them in seeking out the necessary support and help that you need. Supportive and loving families want to be there for you and help you. If you don't have a supportive family, there are school counselors that you can go to for help, and they will be able to guide and direct you to the help that you need. That includes help for your mental health struggles. So if you haven't already gotten help, don't be afraid to ask for it. It's much better to do it now instead of waiting and allowing yourself to suffer needlessly. Because there is help out there, you just need to be brave enough to ask for it.
There's really no reason to feel ashamed about having mental health issues. It's not all that different than any other medical issue that people have, only this one primarily deals with the chemicals in the brain not working correctly. Our brains work on a very delicate balance of chemicals for us to think and function correctly. This applies to all of us. If anything is out of balance it can really affect a persons physical and/or mental well being, and this balance can easily be affected even by something as simple as not getting enough sleep or not eating well. Just like any other medical problem, when your brain isn't functioning correctly we need medical assistance to help correct it. And that can't happen unless we go see a doctor who can help us. You're not alone in this, in your school or in the world in general. Lots of people struggle with these things, but just like you they might feel ashamed or afraid to talk about it when they really shouldn't.
Remember that as important as high school seems and how emotional it can be, it's temporary and really just a small moment of your life. It's essentially a time to prepare you for what you might want to do as an adult. All of that silly petty stuff that goes on in high school can seem and feel important and hard to deal with in the moment, but it really isn't all that important in the whole scheme of things. High school will end in a year or two for you, and you will likely never see any of those people again(or rarely), and what will be the most important thing is what you learned from the experience, both in your educational learning and character building. It's the type of person that you want and decide to be, and how you treat others that is one of the most important things in life. There's a quote I really like by Eleanor Roosevelt who said 'No one can make you feel inferior without your consent'. Which essentially means that despite how others treat you, despite what they say to you, the power is yours to decide how you are going to react. You make the choice. People will make their own choices about how to treat you(and others) your entire life, but it's you who ultimately decides how you are going to allow it to affect you. They may treat you like you are 'inferior', but only you can decide to feel 'inferior'.
Focus on what is really important, remind yourself of those things when life seems difficult, and don't be afraid to find the emotional and medical support that you deserve and need. Along with any medical help you need, there is also a component of what you allow yourself to think that can affect how you feel. I like these 9 tips for 'keeping your personal power'.
https://www.inc.com/amy-morin/9-ways-mentally-strong-people-retain-their-personal-power.html
And you know that we all here understand your love of rabbits. It might be an uncommon interest in your high school, but really there lots of rabbit lovers out there across the country, and I would say most are teenagers and adults(so definitely not a childish interest), and even a few celebrities have them as pets. In fact rabbits are not usually a good pet for a child and are actually a better pet for more mature individuals.
I'm sorry your bun has been having health issues. Just remember if you need any help with your bun you know you can come here and ask and we'll try and assist or direct you to the help you might need when possible. We don't always know the answer, but usually someone will try to help where they can.