with what I thoughtwas the flu .这句话中what引导的是什么从句

Question

I went home from the training of snowboarding with what I thought was the flu.

Answer 1

在这句话中what引导的其实是主语从句，虽然被放在了后面。
what I thought was the flu 在这里是“起因”，I went home from the training of snowboarding 其实是“结果”。