Hey Parth,

the way you are feeling is is normal for the situation you and your mom and sister are suffering, is great from you that you acknowledge how feel and that you want to get better. Your relatives sound a lot like my narcissist siblings, father and relatives on my dad’s side.
They still if they have the chance pick on me and my mum and with time if given any chance they get worst, so is important that you have realised that they are who they are, and so you can start keeping your distance they don’t change and hopefully also your mum starts to keeping her distance for her and your little sister’s sake.

Therapy and have someone to talk to it is quiet beneficial,you could be ptsd, that kind of abuse (emotional abuse) is very hard to fight at first mostly because you don’t have physical scars to prove it, but the damage can be as bad or even worst than physical abuse.

The guy of the link above has help me a lot to understand what was happening to me and to take safety measures. I hope you can find it helpful too.

And I wish you all the best for you and your family (I mean your mum and your little sister)