The biggest difference between being with Draco and . . not being with him, in the sense of intensely hating him, was that while normally Draco would watch Harry carefully and yell at him derisively through the crowd of students at any sign of weakness or discomfort, now, Draco mostly refrained from talking to Harry at all. They stood beside each other, and Harry talked to Ron and Hermione (who pretended not to notice Draco, who returned the favor) and Draco talked to Crabbe and Goyle.
When Harry brushed against Draco, on accident or intent, Draco would look at him and would always return the touch, a hand on his sleeve, a hip against his. But when he had something to say, he looked away; and it was just as well. Harry didn't think it was funny when Tori Mizzentop tripped over the gargoyle feed and hurt her ankle-- Draco probably wouldn't be amused that Fred and George had talked Peeves into pantsing Snape. Their mutual enmity had gone and now they had nothing in common.