Does this make me a bad person?

TW : ED, body shaming, rumors, $uicide im " best friends" with this girl but shes really really toxic. And this is what happened leading to to my question. Im recovering from an eating disorder and she constantly made jabs about my weight and body. About how my waist is soooo big or my hips and tits are so small compared to her( we wear the same bra size so??), my eating disorder cause me to leave my sport which broke my heart but she just dogs on me for it because she still does the sport. She has told my PERSONAL, and i mean like really really personal business to people. She started a rumor at my church/ school that i smoke weed. She shames my face for no reason. She put words in my mouth saying i called one of my closest friends at the time " a waste of space and oxygen"( said friend was suicidal). I lost my entire friend group and had no idea why. There is more but this is long enought as is, so i warned her multiple times that if she kept starting rumors/ putting words in my mouth/ spilling my business that i would do the same to her. Well she decided to tell the loudest mouth we know a very personal fact about me which got spread around, i was did what i told her i would do and said to the SAME loud mouth " she pops pills thats why she so f'ckin skinny." And now shes saying i did that unprovoked. So am i a bad person for this or did i just "defend" my self?????