HELP!! Birth control pill before IVF. Please read question in details..

Hi ladies, I'm starting IVF in Feb 2020. We had an appt last week and they told me to start taking the pill on CD1, not a day which has just been spotting, but a proper bleed. I started the day with spotting and it is now developing into a proper bleed. It is no longer spotting but it isn't a full proper bleed yet either (TMI: there is now lots of red blood but at this stage only when i wipe). Would you start taking the pill tonight or wait until tomorrow night?