no full flow...CD1?

so i'll be calling in the morning to see what my nurse has to say, but i was wondering if any of you ladies would have a quicker answer for me. this is the 2nd time i've taken provera/prometrium to end a cycle. last time, i had 1-2 days of brown spotting with some small clots passed. this evening i had some spotting and one small clot. if this goes the same as last time, i likely won't have a full flow. so would today be CD1? or tomorrow? I was assuming tomorrow, but now i'm not sure. tia!