I think "yes, it should". I think that "before I'm going to sleep" in this sentence is so unidiomatic in my form of English that I consider it wrong. I don't use "before" with the continuous verb form. However, Hatgray, if you are in India, this use of "before I am going" is, I understand, idiomatic."I am going to finish my report before I'm going to sleep."
Shouldn't it be "before I go to sleep"?
Yes, you're right but I generally hear it used where the simple present would be more appropriate (or the future continuous in place of the simple future).I understood that the present continuous was used widely by English speakers in India
"I am going to finish my report before I'm going to sleep."
Yes, that is what I would expect also, but the OP had "before I'm going to sleep." I think we agree about that being wrong in standard forms of English.But I'd expect to hear: I am going to finish my report before going to sleep, without a second I am.