AITA for refusing to let my girlfriend bring her dead dog’s ashes on vacation?

Update below

On mobile. Sorry if there are formatting errors.

My girlfriend (29F) and I (28M) have been together for four months. She had a dog that died a few months before we met.

I have only ever spent the night at her place (I live with my sister and her two kids, so it’s a little chaotic at my place). Gf has a small (2-3 inches tall) urn on her bedside table with the dog’s ashes. Before she turns off her lamp to go to sleep, she always gives it a little tap on the top and says “Goodnight”, as though she is talking to the dog. I think it’s weird, but I have never said anything.

We were supposed to go away for the weekend. On Friday, I was watching her pack, and noticed she took the urn and put it in the top pocket of her backpack. I asked what she was doing. She said she didn’t want to “leave the dog behind”. I told her she was not allowed to bring the urn as it made me very uncomfortable. I didn’t want to see it anytime we returned to our hotel room. I didn’t want her talking to her dead dog after we’ve had sex (ie: before we go to sleep). It’s weird, and frankly, she’s been mourning this dog for too long. She didn’t argue. She simply started to unpack her bag. She told me to have fun on the weekend getaway, as she would not be coming. I asked if she was seriously choosing a dog’s ashes over me. She said she was choosing herself over me, as I could have spoken to her with kindness and empathy, but didn’t. She also said that I didn’t get to dictate how long she’s allowed to grieve. Then she asked me to leave.

She hasn’t replied to my texts. I think she’s overreacting. My sister said she can see both of our sides. Am I an asshole for thinking my gf is weird for being so attached to her dead dog’s ashes?

Edit 1: the hotel was non-refundable and only a three hour drive, so I went on the trip without her.

Edit 2: she started seeing a psychologist around the same time we started dating; she hasn’t told me any specifics, but she said the trauma of suddenly losing her dog brought to the surface other trauma in her past. This is why I think she has been mourning for too long. She is still attached to the dog, even after seeing a professional on a regular basis for several months.

Update (and I’m sure this will make a lot of you happy): I get it. I’m an asshole. I texted my gf to say I’m sorry for how I spoke to her and for dismissing her feelings. It was wrong. I also said I would like to apologize in person, and offered to bring over her favorite take out. She said “all good. dont worry about an in-person apology. i gathered the things you’ve left at my house. let me know when you would like to come pick them up”. I’m hoping she will still hear me out when I go to her place.

Edit 3: To those of you dm’ing me who think I’m NTA, but won’t post a public comment due to the risk of being downvoted, please stop. That is cowardly. To those saying my girlfriend is a lunatic, a sociopath, unhinged, a trauma dumper, has endless emotional baggage, in need of a mental institution, etc, please stop that, too. While myself and others may not understand what she is going through, that doesn’t automatically make her mentally unstable. She has a good heart and a good head on her shoulders. Name calling is unnecessary and borderline crueler than I was.

Final update: I shared this post with her, thinking it might help her see that I was wrong and am owning it, and maybe it would open the door to a discussion. That blew up in my face. I probably should have deleted some of the questionable comments i made in this thread. She texted to say: “your things are now in a garbage bag on the porch. pick them up sooner than later so they aren’t stolen. goodbye [my name]. please respect my wishes and don’t text me anymore.”