I feel like a horrible friend for flaking last minute

Yesterday my friend childhood friend and I were planning to have a girls night to go see Elvis for the third time. Within about 2 hours of the movie starting, my friend invites me to his going away party because he’s moving to Mississippi and I’ll probably never see him again. I was so stressed but ultimately decided seeing my friend before he left was more important— but I at the same time felt so horrible for canceling girls night. I apologized relentlessly but she’s still upset with me. I feel like I was damned either way but I just feel incredibly awful for hurting my childhood friends feelings for flaking. Any advice?