To me, it IS too late to FILE complaint to HR. Actually, I probably will never do that (my personnel choice, though :-))
It seems to me that you are not so happy for such a long time in this job/group! Give yourself a break and show them your pride and move forward.
As your previous post said, it's hard to find jobs currently. It may take a little longer to find your next job, but somehow, I also would think it's true for what your manager said, you at least have a job within this company in months and you can use this course of time to find a new one. Then you will have options when the time is coming.