Two years ago, I got badly hurt and I didn't get the support from my family which I needed that time and it made be rebellious. So that time knowingly but not intentionally, I created fight between my mother and her sister. I feel so bad about it now. I tried my best to solve the issue after that but nothing helped. I feel so bad and can't forgive myself for that act. But that all happened because I was hurt and it was for the first time ever, I was experiencing depression.
I am sorry to read that. Maybe confessing to them what you did would help things. If you do not think that would help, then what you could do is try to make them both feel more appreciated (by buying them gifts and being extra kind and considerate toward them). If they both start to like you more, that could give you many opportunities for improving things between them.
What you should also do is constantly ask for God’s support and guidance in fixing this problem (and every other problem). You can start praying tahajjud (see here for more information), which would make it more likely for your prayers to be answered inshaAllah.