AITA for telling my sister our relationship is one sided?

AITA for telling my sister that our relationship is one-sided?

I (23F) told my sister (20) yesterday that our relationship feels very one-sided and that I am always putting effort in when she only tries when it conveniences her. I am the oldest, and our parents are divorced so it’s only ever just been us. It’s hard for me to hold a conversation and I don’t have very many friends, and no significant other, so it’s really just me and my sisters. All throughout my childhood, M wouldn’t do things she didn’t want to, even if it was a group bonding time or family time. She’d complain until everyone hated it or she went home. Beach or boat trips were too sandy. Vacations were never perfect. Even trips to visit family were boring and too peoplely (we never forced her to interact with them. She was just 10-12 and couldn’t be left home for a week in another state).

I’ve always struggled with my mental health, and I had a convo with them about it. They said they wanted me to talk to them instead of bottling it up. I told them it was hard to do that because I was forced into a role model and parental figure for them. We agreed to all talk when something was bothering us, and it was working for a while.

Now the past couple months have gotten worse. When she needs something, I’ll help her, no strings attached. If she needs a ride, I don’t ask for gas money. If she wants to hang out, I’ll drop what I’m doing, even if I’m exhausted or busy, because I want to spend time with her. But if I make plans she’ll go along with it until day of and cancel because ‘she didn’t feel like it’. We both read and we’ll swap favorite books, and she always pushes me to finish her choices, even if I don’t like it. And she do, because she wants to talk to me about it. But she won’t always finish mine. She’ll borrow my clothes, but my stipulations were that they get washed after and she doesn’t take them to our mom’s house where she lives half the time. She took my leggings - my only pair - last week and refused to bring them back for me and I lost it.

It wasn’t even the leggings that I was angry about, but she wouldn’t take responsibility. She just kept saying that I was ‘trying to place blame on someone’ and I was overreacting. I explained to her how I felt used and this relationship felt one sided and she said she ‘drove a lot last week and didn’t even ask for gas money’.

Now she’s angry at me and my dad is too, for ‘trying to tear the family apart’. They both think we had a normal sibling relationship and I’m getting too emotional. I feel like I’m all alone and used. None of them have ever once done something I asked unless it benefited them. Am I really overreacting?