hi op, I think it's great that you've realised this

moving forward, what you can do is to acknowledge and accept this part of yourself that's being all negative. acknowledge what you felt/did and realize why you felt that way and any issues that led up to it. then tell yourself that you accept everything, because it's still a part of you, regardless, then work on those issues. I'm currently going through something similar and it is only now that I realised the big picture (multiple people had to tell me the same thing over and over again) and I'm still working on accepting myself first. don't be like me and rush things though. don't be too harsh on yourself

if in the future you find yourself beating yourself up for this or if you feel anxious when this comes up in your mind again, repeat 'I acknowledge you' over and over again regarding the thought. speak to it kindly