My Friend Keeps Embarrassing Me

My friend is turning into a bully and I don't know what to do to stop her. I tried calling her out on it, but she told me I was "being too sensitive" and "making a big deal out of it."

She's been teasing me about my body since I can remember, and lately she started lifting my shirt every time our friends are around.

The first time she did it was in class. We were with four other girls, chatting, She lifted my sweater in the middle of the conversation. The other students weren't around, luckily, but I didn't know those girls very well, so it was particularly embarrassing.

I feel like she's doing it on purpose to humiliate me and make me look weak in front of others.

She always gets away with it because my friends think it's funny that I get treated like that. They laugh every time and tease me about it for days, which is frustrating because I'll always be known as the girl who gets her shirt lifted for their own entertainment.

The second time was in the middle of gym class. I was leaning down to tie my shoes and she came up from behind and lifted my t-shirt. She did it so aggressively that I almost tripped.. At that moment, I was bursting with anger but held myself back. I didn't speak a word to her for the rest of the day.

Last night, we were sitting on the couch with two other friends. I was lying upside down, with my legs over the backrest. She suddenly pushed me to fall on my back. This time, my shirt only rose above my stomach so I immediately pulled it down to cover myself. My friends started laughing, as always, while I was trying so hard to contain my anger and embarrassment, and not burst into tears.

I've had enough and I can't take this anymore. I want to get back at her for everything she put me through. I want to humiliate her and have our friends point at her and laugh. What should I do?