Trying to conceive

So we are trying for a baby! I got my Paragard (non-hormonal) out August 2. Doctor told me to have a normal cycle before we officially try. My periods have been completely normal while on Paragard, 5 days, on time, every time. August, I had my normal period/cycle. Here comes the fun!
Well, September and October, both my “periods” were 3 days total. First day was extremely light/spotting, medium bleeding the second day, and the third day extremely light/spotting. All pregnancy tests have been negative.
I have an appointment on the 25th.
Was wondering if any ladies had any insight, or had this happen to them as well?