C.W.
More than likely you were ovulating. If you've been on BC for a long time you wouldn't have had this so this is going to be something new. After having been on BC for years my husband had the big V and all of a sudden I started doing this same exact thing. If you goggle ovulation and read about it, during this time your discharge will become thick, have a very mild color and sometimes can be sightly blood tinged, and will even notice a slight smell sometimes. Keep in my your body is going to take a while to keep back to normal so you may not ovulate at the same time every month for a while. Also, I never ovulated before kids (hence the reason for invitro) and now every month I can tell exactly when I ovulate and exactly 2 weeks later I will start my period.