All praise is due to Allah, peace and blessing be upon the Messenger of Allah.
Your prayer and fast are correct , and you should not make up for them, and we ask Allah, The Almighty, to duely reward you for these acts of worship. Your menses start once you see blood because the situation remains as such unless there is certainty or predominant conjecture, as per the Fiqh maxim: 'Certainty is not removed by doubt'. And Allah knows best.