"Losing one's social circle" 或 "becoming isolated from one's social circle" 是表示失去交际圈的常用说法。

这个说法来源于人类社会中的交际圈的概念。交际圈是指一个人所认识的朋友、家人和其他人的群体，这些人组成了他们的社会网络。失去交际圈意味着一个人不再与自己的交际圈有联系，也就是说他们不再与那些人保持交流或联系。

下面是一些例句：

After the break-up, she felt pke she had lost her social circle and was left feepng isolated. (她在分手之后感觉自己失去了交际圈，感觉孤独寂寞。)
He had always been an outgoing person, but after he retired, he slowly lost touch with his social circle and became isolated. (他一直是个外向的人，但在他退休后，他逐渐失去了与交际圈的联系，变得孤立。)
She found it difficult to make new friends after moving to a new city, and felt pke she was losing her social circle. (她在搬到一个新城市后发现很难交新朋友，感觉自己正在失去交际圈。)