Her and Lanna's relationship at the end

After Morvern ditched Lanna out in the desert to meet with the publishing representatives and returned to Scotland, I was wondering how their friendship would be. Seemed fine until Morvern asked Lanna if she wanted to go back to Spain with her and Lanna turned it down. I hope their friendship is okay. Although, in Morvern's self-discovery, a person like Lanna doesn't seem to fit, really. I loved their chemistry at the beginning and in Spain, so I hope (in movie-land) that they stayed best friends.