abusive neighbours

hi, there.
i hope you would maybe find my situation familiar and maybe have some advice. so, here is a thing.
I have recently moved in to a new room which is part of the dormitory-type house. I have not been very attentive to my neighbours, and since they never showed any interest to greet me, I have never greeted them too, which maybe might have been a mistkake, however, i am under a great emotional pressure right now, because i have cut off all communication with my parents and left their home.
So, after I moved in, i allowed my cat to walk on window sills, i wanted to give him a little bit more space, because he's normally a house cat and does not have much space, so i thought he would enjoy getting some fresh air from outside.
one evening i was rudely asked (without even saying hello or anything) whether it's my cat who is walking on window sills. I couldn't see that woman in the dark ( we were outside in the garden), and i asked her which floor she lives in, as i don't know. she very rudely said she lives in the 2nd floor, just as i do, she said. she started shouting on me that the cat entered her room twice at night, I apologised, but she was extremely rude in the manner she spoke and that disbalanced me, so i started shouting at her too and that's how the conversation ended.
another time, another woman came to me in the evening as i was locking my door and asked 'when will this pile of rubbish be taken away?' in a rude manner (it was a former tenant's belongings left in the corridor which he was to take with im sometime those days). Again, I wasn't at my best, I started explaining that was another guy's stuff, and that it did not even concern me.
And last but not least, one evening I was again in emotional turmoil after a conflict with my mother, i was sitting alone in the room, and I hear the doors getting opened and a woman shout 'parasite' at my cat. I came to the door and saw some other woman standing in my corridor. I asked what the heck she thinks she is doing and asked her to get out of my flat. She started shouting at me that my cat nearly pushed a flower pot from her window sill and that i should close my wondows. I told her sorry for the flower pot (idiot me for doing that) and said she should knock on the doors if she wanted to talk about that, she said 'don't teach me', I said to her again that if she does this again, i will call police, she then shouted in my face 'don't teach me' and then said that I would have had to pay for her losses if the flower pot was damaged. I was taken aback by her behaviour, I was speechless by this rudeness, so I just closed and locked the door. Later I check her window sill, there wasn't a single flower pot.
I am afraid to even go to the shared kitchen, toilets or bathroom, I am afraid to be attacked by them again.
I don't know what would be the best way now to behave. What should I do? How should I approach those women?

I feel like I am a person whom everybody else enjoys bullying, it has happened to me before as well. I don't know how, but I evoke somehow aggressive reaction to people towards me. Is it because I try to fight back, that I attack them back and they see that they can toss me around? Is it because those kind of people need some aggressive conversations, because they don't know how else to communicate with people?
I feel terrible, it was the last thing i need when being so emotinally vulnerable and weak and when I need to put all my energy into solving relationships with my parents.
I don't know how come people can act like this, like savage animals, it makes me sick and desperate.