I felt left out and unhappy.

我觉得自己被冷落了，很难过。

youdao

Joe felt left out when he didn't get invited to the party.

乔没有受邀去参加派对，让他深感受到忽视。

youdao

I just wanted to be the same as my friends and I felt left out.

我只想跟我的朋友们一样，而我感觉受到排斥。

youdao

He says he has felt left out of the ante-natal process.

BBC: News | Health | Fathers: Out in the cold?

Children who didn't own the magic sheet or the magic crayons felt left out -- they could watch the show, but they weren't participating in the whole experience.

CNN: Winky Dink and ... Bill Gates?

He felt completely left out.

NPR: War on Terrorism Takes Toll on Military Families