How do you know about the ovulation ? did you do BBT or vaginal mucous test ?
One can always become pregnant near ovulation days , within 48 hrs.If you have pinpointed the exact time then you are less likely to become pregnant as you said 4 days.It is better to wait till you miss your periods and go for the pregnancy
test till then take safer medicine for nausea like folic acid
, doxilamine combinations if you want to continue with it. Still if you feel you can go for an ultrasound
to see any endometrial thickness or an early gestational sac
which is less likely to be there.