I haven’t been my best self lately and I’m ruining things. I don’t know what to do.

I recently turned 18, and I'm feeling really lost right now. It seems like I've changed into someone I hardly recognize. I find myself getting easily annoyed and frustrated, and I tend to push people away. I know I've been acting rudely, especially when I disagree with someone, and I regret it deeply. I want to be better, but in the heat of the moment, I end up hurting the people around me. I don't want to take my loved ones for granted, but I feel like I'm not in control of my actions. I'm worried that I'm not a good person anymore. I only have a couple of close friends, and I'm afraid of losing them. I've hurt someone I love because of my behaviour, and I don't want to keep hurting them. I'm starting to wonder if I'm just a bad person. What should I do?