Thanks for coming back and sharing with us how you feel. I hope you are getting by and safe. Know that you are worth it, that you deserve the things that life has to offer, and that you cannot blame yourself for all of the shortcomings you feel that you are experiencing. School is hard as it already is, and I'm sure that your teachers want to be there for their students. Do not feel like talking about your health, mental state, and emotions are a waste of time for anyone. It is important, vital, and key to getting better. Discussion plays a big role in understanding yourself and finding support so please continue to find people to open up to such as your teachers. Maybe you can send them an email if that is easier for you. I know things may be more difficult cause of COVID.
With your grades, it is not the be-all, end-all. I am someone who was a decent student, but in my last year of high school, I did not put the effort and time into my HSC when I knew that I had it in me to do a lot better. I was a really bad procrastinator and was not at the best place mental health-wise during that time as well. My ATAR wasn't the best and I couldn't get into the course I wanted to do directly. The thing with Uni, is that it's a new start and there is actually a lot of pathways into different courses. For me - I changed degrees 3 times to finally land in the Honors roll for psychology. I didn't think I could do it and I doubted myself so many times but I did it, and you can too.
Be kind to yourself, love yourself, and fight for yourself because you deserve it!
Hope you are okay friend. 💙