AF or possible implantation???

I have PCOS and my cycles are extremely irregular. My last cycle started 9-12 and I did my first round of Femara 9-14 through 9-18. I had an ultrasound on 9-25 and my RE said I should ovulate some time over that weekend. It's coming up my tww and I have had some spotting the last few days. Nothing on a panty liner only when wiping. I have been bloated, gassy, nauseated, sore breasts, cold symptoms, low appetite, fatigue. AF or possible implantation? When would be a good time to test?