这是口语句子。说话人可以临时杜撰一个程度副词—— God knows how去修饰一个副词，或no one knows what 或 I don't know what 修饰一个名词。例如：

He came from (God knows how) far away. 他来自很远很远的地方。

He ran at (you can't imagine what) a fast speed. 他跑得速度之快你无法想象。

括号内部分可以省略不用，但缺少了程度很高这层意思。

Without friends, I would have been reduced to I don't know what a miserable creature.

= Without friends, I would have been reduced to a very miserable creature.