Left Out! Inside Caitlyn Jenner's Lonely Secret Life

It's been more than a year since Caitlyn Jenner dropped the bombshell news that she was to begin living publicly as a woman, but the Olympian turned reality star is still on the outs from her famous family, RadarOnline.com can reveal.

On Sunday night, Caitlyn's daughter Kylie celebrated her 19th birthday with a huge Hollywood bash, and nearly every member of the extended Kardashian-Jenner klan was in attendance. Though she had returned to Los Angeles from London, Kylie's former father, 66, was the only one to skip the festivities.

Just last month, Khloe iced her onetime stepdad out of her 32nd birthday party.

"It's really bad between Caitlyn and the kids right now," an insider tells RadarOnline.com. "They still feel she hasn't handled the transition well with them at all. Nothing has been resolved."

As RadarOnline.com has reported, many family members, especially young Kylie and Kendall, 20, felt blindsided by the gender change, and found out about it through the media.

"The girls still feel abandoned and betrayed," the source explains. "It's a sad situation."

As a result, Caitlyn is shunned from family events, and often struggles with her overwhelming transition alone.

"Caitlyn underwent many surgeries right away, and the whole process has been very difficult for her, physically and emotionally," the insider reveals. "Sadly, she doesn't feel like she can confide in anyone during her time of need."

Despite having six children, the star "feels like she has no one."

Of course, she also has suffered another debilitating blow. The star's E! reality show, I Am Cait, has been canceled, RadarOnline.com recently reported.

Should Caitlyn attempt to repair her family relationships? Sound off in the comments.