I fully agree with this advice as to a way to communicate your actual feelings in a sentence. Emojis don't work here, but the difference between

"I have no idea what I'm doing... :D"

and

"I have no idea what I'm doing... :("

is a large one, and having that to communicate it is quite handy.

THAT SAID, to @ccakes -- while I agree with your statement, it unfortunately doesn't help the OP. They specifically said that they have a problem with INTERPRETING comments in the worst possible light. The solution for that will not be to use more emojis themselves -- they would need their coworkers to do so.