Did I overreact about my sister's dogs peeing in my bed...again?

When my SO decided not to be a part of the babies life I moved in with my Dad and Aunt(who might as well be my mom), taking over the guest bedroom. My sister and her husband come into town pretty regularly and usually sleep in that bed. The first few times of me living there I didn't mind so much, but when the baby stuff started being merged I got a little teritorial of what is now MY room.

Seeing that this room is no longer the guest bedroom, it is the baby and I's, I have the right to not really want people in it. The baby and I should not have to move out everytime they come into town. Regardless, I allowed them to sleep in the bed last time they came with their 2 chihuahs and newest puppy. I went to change the sheets Sunday and there were two huge pee stains on my mattress cover. I got enraged. This is not the first time I have found poop and pee remants and the 2 previous times I didn't say a thing not wanting to be ugly, because my sister and I had already argued about how it was no longer a guest bedroom and I didn't really want the "untrained" dogs in there.

I couldn't keep my mouth shut this time. I sent my sister a text message telling her I was not amused, I was having to spend hours cleaning this mess up and her dogs were not allowed in my bed. In reply I got that I was rude, and that her dogs do not pee in the bed. I just lost it, I really did. I don't know if some demon took over my body or if it was just hormones, but I went crazy.

When I finally got calmed down my Aunt called her to rectify the situation and I could hear the conversation. I picked up on that I am a drama queen because I start stuff every time they come into town, I am hormonal and I make her feel unwelcome so she won't be back. The last time we argued she told me her life does not revolve around me and the baby, when I had done the sex ultra sound around her schedule, the birthing classes around her schedule, and the baby shower...around her schedule...

It doesn't matter that she threw me a baby shower and left town without even picking it up, that she leaves trash laying around our house, that her dogs pee in the bed, and I have to move out of the "guest bedroom" because they are guest. Nope, I am territorial, hormonal and a drama queen. So over it. I understand why my dad and aunt took her side, they deal with the dogs so they can see my sister. How do I deal with this?