HI and thank you so much for this query. May be late already fro the dates you have posted but i guess the information is going to be of great help in future similar situations.
If you have sex on the 5th day of your cycle, the chances of getting preganant are very very low. Taking ECP shortly after that further reduces the chances. Also, having the withdrawal bleed even makes the probability very very low.
ECP often distorts the cycle though it eventually gets a new rythmn for itself.
f you have not still seen your menses by this time, then you at least need a pregnancy
test and further investigations if warranted identify the cause.
Please, beside having unwanted pregnancy from an unprotected sex, you run the risk of transmitting or contracting sexually transmitted infections. I will kindly suggest that you always consider having protected sex unless otherwise indicated.
Hope you find this information useful
I wish you good health.
Dr. Ditah, MD.