Anna, sorry for the late response. Here's hoping you did WAY BETTER than you thought. Don't get discouraged. I know that you are more than capable just by reading your posts. You know your shit and you work hard. And you've already passed AUD and FAR with excellent scores.
The Gleim SIMs are good practice, I believe, and yeah, as boring and horrendous as the book is, it really pays to read it. And I've found that no matter how counterintuitive it may seem, the Gleim suggested study steps really are effective and helped me more than doing it my way. Take the MCQ 1 even if you don't know anything about the subject matter. Watch the audiovisual and highlight your book as you go. Do the TF test. Then read the chapter, take the little quizzes at the end of every subunit (in the book), and maybe create some flash cards as you go. Then do MCQ 2 and keep doing MCQs until you nail it, then SIMs. But honestly, it sounds like you've got it all under control. Maybe just not enough time.
Did you feel horrible coming out of AUD and FAR as well? I've never come out of a CPA exam feeling like I did well.