Am I (26m) wrong for wanting to end a 5 year relationship over what (24f) gf possibly did?

Hold on tight. This is a fucking shit show. Literally.

This morning I woke up and went into the bathroom that my partner and I share. When I looked down, there was what appeared to be toilet paper with poop on it on the floor. Now, this isn’t the first time this has happened. Once before, I found the same thing. Dry paper with poop on it next to the toilet.

The first time when I asked what the fuck poopy paper was doing on the floor, my partner said “maybe the dog pulled it out of the toilet or trash can.” Weird, but a reasonable enough explanation for me to move on from it. Our dog has been found snooping in the toilet and trash. I’ve never seen him go after human shit, but it’s possible.

Fast forward to today. My partner leaves earlier than me for work and spends 30 mins to an hour in the bathroom. Like I said I go to take a shower and find the dirty gift. The toilet paper was not wet and it didn’t look like it had dried after being wet. So it wasn’t pulled out of the toilet by the dog.

I sent a picture of it to my partner asking “wtf is this, why is there shit on the floor” to which she replied:

“That’s 100% not me? I don’t even put toilet paper in the trash. I’ve seen you put toilet paper in the trash which is fine but like I’ve definitely seen it.”

I’ve never once put toilet paper with poop on it in the trash can. I also use 1-2 squares when I wipe and flush. This was 5-6 squares.

She then proceeds to tell me I am attacking her. I feel like asking “hey why is there shit on the floor of our shared space” is a perfectly reasonable question to ask someone. Am I going crazy? Is this gaslighting?

I am so confused and disgusted. She keeps bringing up “gross” things I’ve done and saying she cleans stuff up without attacking me, but I have never left shit on the floor. I am so close to telling her to get out.