Implantation a bleeding?

Jessica
I am usual a 28 day or sooner cycle.   on cd 26 o had a dime side pink/red spotting that was it.   cd 27 again a dime size spotting but brownish color.  today cd 28 I took a pregnancy test and it was negative.   still have a little brown spotting.   
I iust finished up a <a href="https://glowing.com/glow-fertility-program">IUI</a> cycle with Gonal f and Ovidrel.  
Anyone been thru this?  what was the outcome?  
I can schedule a blood test Wednesday if AF doesn't show