My mom 42f is really mad at me 16f right now.

My sister 11f is a bedwetter, she wets every night and wears goonites ( pull ups for kids who still wet the bed ) for it. Bedwetting runs in our family, i wet the bed until I was 14 and so did my mom.

Last night my mom came to me and asked if my sister could borrow a pair of my period panties, ( it felt really weird cuz my sister and me don't borrow each others panties ) My mom said she was out of goodnites. Our parents had ordered her a box with 4 packs and it was supposed to have arrived that day but it hadn't for some reason. So she needed to wear a pair of my period panties for her bedwetting that night.

I said no because it's MY underwear and I don't want my sister peeing in it! And I doubt she'd even fit in it.

She said it wasn't a big deal and she promised to wash them the next day. But i kept saying no, I don't want her peeing in my underwear that's just eww.

My mom got really mad and said I was being a bad sister and stormed off.

Then today she yelled at me saying my sister had wet her bed cuz she had no protection. And now they had to wash her sheets because I was a jerk.

They are punishing me by making me go up to the store to buy a package of goodnites for my sister just in case the box doesn't come today, they're gonna give me the money but the punishment is I will have to go in and buy pull ups.

I love my sister very much and feel bad that she wet the bed but just don't feel comfortable with her wearing my underwear.

I don't know what to do now, I didn't want my sister peeing in my underwear and didn't think it was that bad but my mom is really mad and thinks I was being mean.

AITAH?