Billie Eilish couldn’t stop laughing when she and her brother Finneas O’Connell won an Oscar for Best Song for “What Was I Made For?” “I had a nightmare about this last night,” Eilish said after being presented with the trophy during the Sunday, March 10, ceremony. “Thank you so much to the Academy, I just didn’t think that this would happen. I was not expecting this. I feel so incredibly lucky and honored. Greta [Gerwig] – where’d you go? I love you! Thank you for this!” “I’m so grateful for this song, and this movie, and the way that it made me feel. This goes out to everyone that was affect…