From Pocket Comics:
An ugly duckling?!
Jouka Sourin Academy is a school for the sons and daughters of elite families, but the impoverished main character, Ug-Fatty Saotome, has been bullied there for six years. She's forced to face the leaders of the two bullying groups in the school, but luckily she has strong mental fortitude! Will she be able to survive the game her enemies have set up and graduate?
A romantic comedy featuring an Ug-fatty who fights back!

Official Taiwanese Translation
Official English translation on Comico's Pocket Comics app