Reconnected with Sister after a few years

My sister and I were raised in the same household with our nmother. She’s two years older than me so we did a lot of things together. I’m not sure we were ever super close but we did hang out a lot. We both experienced emotional trauma from my mother, but in different ways. I would say she was the scapegoat and I was the golden child. We drifted after we became adults, but became close again after both going no contact with my nmother. We both tried to reconnect with my mother at the same time and things were ok, but soon after my mother fell back into her old habits and my sister and I decided to cut her off again. We’ve both been no contact with her for about 3 years at this point.

About two years ago, my sister stopped talking to me. It sucked, but I understood. There was no malice there, she just needed to heal and frankly I did too. During those two years, I didn’t have any contact with family and did my thing. It was nice, I felt like I was finally past all of the trauma I grew up with.

My sister and I (both in our early 30s) recently reconnected about two weeks ago and it is bringing up a lot of old feelings and my mental health is deteriorating. I know it’s partially because we are both in a place where we can talk about everything that happened and finally understand each other without our mother trying to pit us against each other. That should be a beautiful thing, but I just feel awful all the time like I’m a kid again.

Has anyone ever experienced such a backslide? I’m worried that I won’t be able to have a relationship with my sister without feeling this way. I don’t know where to begin to get through this feeling. I really don’t want to cut her out because I’m so happy we’re finally talking again. I also don’t feel like it would truly help anything, it would just be avoiding whatever is going on. Thanks for reading this whole rant and I appreciate any advice.