In this passage, the narrator describes feeling extremely nauseous, to the point of almost vomiting, but helpless because they haven't eaten. They express a sense of physical weakness preventing them from leaving their room or taking action. The mention of confronting Fang with a roundhouse kick suggests a desire to fight back or act forcefully if they had the strength.
"I feel like I'm going to HURL. Which, even if I wanted to do, I couldn't do, because I haven't eaten. I can't even drag myself out of my room. And while I'd be able to muster the strength to roundhouse Fang until he begged for MERCY, I'de be mush around an Eraser." The narrator illustrates their vulnerability and frustration, highlighting a mix of physical weakness and mental resolve to fight when capable.