Thank you for your question! I’ll offer you my thoughts on this for your contemplation, but as always please take them with a grain of salt. I may not have a lot of personal experience with bullying, but as a fellow soul I can relate to your suffering and this is the universal ground that I would like to start from.
It may seem overstated, but it is crucial here to know and deeply accept that you are not alone. Bullying, like all suffering, is a universal human experience. To break the suffering, try to look past the pain-body and recognize the universal qualities to the bullying situation: the bully is also suffering. Whether you know their situation or not, recognize that there is something in you that they are afraid to confront in themselves. We are all mirrors of each other in that way. Use this sentiment to muster up compassion for this person, as difficult as it may be. They are unaware, unawakened, and they are suffering for it.
Meditation can be helpful. You can use meditation breathing exercise, or even mantras to help stay centered. Repeat that you are strong. Repeat that compassion ends suffering. Repeat that you are never alone.
Above all, remember that bullying is a form of suffering. When a level of consciousness is reached where we can observe experiences, emotions, and thought processes that drive certain behavior we then become free to make new choices. It is then that we can see our differences as beautiful expressions of harmony. This brings compassion, which ends suffering.
Again, take my words with a grain of salt, but I hope I could help even in some small way. Namaste and stay present!