My roommate bought a fridge without asking and now I'm the bad guy?

So I need to vent about my roommate because I'm honestly just tired and confused. I live in a dorm with two girls. One of them, let's call her Anna, is... something else.

So the other day, Anna and our other roommate were discussing buying a fridge. I was in the room, yeah. But I was in my own head, feeling like crap (depression + new meds are a fun combo). I wasn't part of the conversation. I didn't give an opinion. I just existed nearby.

Next thing I know, they've bought it. They bring it in, and Anna turns to me and goes, "Okay, your share is ~$30."

I was stunned. I said, "Hold on. You never actually asked me if I agreed to this or wanted to pay for it. You just... decided."

And you know what her logic was? "Well, you were here. You heard us talking about it. That means you're in."

Seriously? Since when does overhearing a conversation equal giving my consent and opening my wallet?

I told her straight: "Hearing you talk is not the same as you asking for my opinion or getting my agreement. I'm not paying for a decision I didn't make."

And then she just... exploded. Started yelling about how I always ignore her. That's her big thing now. Because I was quiet and kept to myself when I was struggling, in her mind that means she can just make assumptions and decisions for me.

The funny part is, she never had a problem finding me to actually ask if I wanted to go see a movie or go somewhere. But for a fridge? Nah, my silent presence in the room was permission enough, apparently.

This isn't the first time. She once bought me a ticket for some university thing after I told her I wasn't going. Her logic was "so you'd have a choice." It just felt pushy and weird.

Now she's walking around our room like I hurt her. Because I didn't just smile and pay for a fridge I never agreed to buy, and because I dared to point out that her logic is nonsense.

I know what I should do. I should actually ignoreher. I should just not react. But it's so hard when someone is constantly rewriting reality to make themselves the victim. And we have to live together for who knows how long.

I guess I'm just looking for... I don't know. Has anyone dealt with this? How do you live with someone who acts like this without losing your mind? How do you even talk to them? Any magic words to make it stop?