Question

I also was glad that he stopped coming是什么从句？

Answer 1

I also was glad that he stopped coming.
that从句有两种说法：
一种：是形容词宾语从句，比较常见形容词：glad, sure, happy, afraid
如：I am sure that he will come.
另一种：是状语从句，表示原因。
另：also一般位于be动词后，行为动词前。

Answer 2

这个句子是be glad that句型，that引导的从句是形容词glad后的宾语从句，即所谓的形容词后的宾语。另外副词also的位置和was调换一下更好。