We can't imagine.

Ariana Grande was noticeably missing at the Mac Miller tribute concert in LA last night, and apparently the songstress just couldn't bring herself to attend, as she's still highly emotional following her ex's tragic death in September.

"[Mac's death] is still too painful for Ariana. She is still deeply grieving and chose to pay respect in her own way,” a source dished to Radar.

The pop star is throwing herself into work to cope with the loss.

"Ariana is now focusing her time and energy on her music and upcoming tour, which she is very excited about. It’s what Mac would want,” the source added.

The chart topper paid tribute in her own way, by wearing her deceased love's hoodie and cuddling his dog Myron, who she took in after his passing.

So sad!