下面这句话中feeling这部分做的是整个句子的什么成分?我知道是非谓语,我问的是句子成分.

Then I left it,feeling a weight at my heart such as I had never had before.
现在分词短语feeling a weight at my heart such as I had never had before在句中做原因状语.
句意是：“于是我离开了它,(因为我)感觉我心里有一个我过去从未有过的这样的负荷”.