Do you ever regret dropping your friends?

I recently ended a friendship over something from the past, and I’m honestly a wreck about it She used to talk about me behind my back, and she’s still close with people who bullied me all throughout middle and high school. Weirdly, that never bothered me much since I’ve made peace with them. But she also stood up for me more than once and was genuinely there for me when it counted. Another friend pushed me to cut her off, and I did, but now I’m second guessing everything. Would love to hear other experiences and if anyone’s been through something similar