Pregnancy happens when a sperm meets an Ovum ( female egg ). While millions of sperm are deposited in the vagina at each act of sex, the ovum release happens only once a month ! The ovum released also has a life of ONLY 24-48 hours. Hence pregnancy happens ONLY when the sperms meet the ovum in that period. I hope you were getting ultrasound done for your ovulation. This is a serial ultrasound and it is done daily from 10th day of menses to assess the growth of the ovum. usually the gynecologists give inj HCG when ovum size is mature e.g 18-20 mm, depending on whether you were given any medicines of injections to help the ovulation in the first week of menses. Your doctor gave you inj HCG 10000. This brings about a release of ovum about 36 hours after the injection. Hence the advice to have physical relations on 20,21 October. After this time any relation done is purely for pleasure and it doesnt make anyone pregnant. So out of 2 days you have utilised 1 day and so now justw ait for the menses. if by chance you have conceived, you will miss the period and this will show a positive urine pregnancy test if done on day after missed period. so wait for menses. if missed, do a UPT. if menses come, you havent conceived and you need to start the process again next cycle.