Just be nice

I am not looking for advice just space to vent. I literally sit 10 - 12 feet away from another admin who's been here for 6 years, no walls, just open lay out. I am newer, replacing a beloved former admin who retired after 26 years and was the Regina George of the office. I have been in this role ~3 months so still learning the ropes by trial and error. My co worker and her former coworker (retiree) still keep in close contact. It feels like everything I am doing, especially the mistakes I am making are being reported back. Regina has been gone about two months and came back to 'visit' and go to lunch with me coworker. Barely gave me a sideways glance and this is after I spent 3 weeks shadowing her so she knows who I am. She did manage to say 'oh I was expecting you to call in a panic or crisis but I haven't heard from you'. Well since you never gave me your contact info, that would be hard to do... She is also invited to our Holiday Party and I am dreading it.

Since there is a lot of down time I try to make small talk, be open and friendly with my suite mate She sneezes, I say bless you, get nothing. Someone asks for me to do something, she goes and does it but doesn't tell me..... it's like getting a dozen small paper cuts daily and I just end up mumbling under my breath. She is super nice to everyone else so it's hard to not take it personally. There are times when she is friendly to me which confuses me further. Any who thanks for reading and letting me get this out