breakups

I just broke up with my friend and I feel really bad. they were really rude / abusive to me, and had a lot of mental problems that i didn’t have the capacity to deal with myself as another person suffering from mental illness. i couldnt really sustain a relationship with them due to their attitude 

they were going to try and recover in some spaces but after what they did to me, and with all the parts of themselves they weren’t going to work on, i really just didn’t want to be friends with them anymore. so I ended the friendship. 

i told them I was breaking up with them in a garden with a building next to it. they cried really loudly, and I wanted to try and comfort them, but they were walking away from me and I was scared so I just…left 

i feel really bad but also they weren’t a good person for me to be around. but I can feel how hurt they must be from their perspective. I feel sick right now. i just don’t think I was the right person for them. they’re probably breaking down right now and I left because I was scared. luckily school is in the next week so ill be able to focus on that instead

ive told them that they can come to me if theyre in trouble or have something really important to tell me since we’re in the same school 

am I the bad person here? did I leave a mentally vulnerable person behind? i feel like I have but I have mental problems too and it really just wasnt working out. i just need advice