Hallow Dear,
There are few issues in your query which need clarification to you. Let me explain one by one.
1. If you miss just one pill during whole cycle of birth control pills, the effect of the pills remains and they do not fail. So the chances of
pregnancy are almost nil due to missing of one pill.
2. On 6th day of the menstrual cycle, there is no egg present for the fertilization. The egg is released (ovulation) 14 days prior to next expected menses. The egg has life of 24 hours while the sperms are active for 72 hours. Hence a period of about one week around the day of ovulation is the fertile period. Unprotected sexual intercourse in the fertile period is most likely to result in pregnancy. Your intercourse was far away from fertile period.
3. There only one method by which you can reliably detect pregnancy just one day after missing period; and that is
Beta hCG test. This test can diagnose pregnancy even few days before missing period. The other home
pregnancy tests which are performed on urine are reliable 8-10 days after missed period. Earlier, they may give false negative results.
4. If you had
diarrhoea after
Amoxycycline (which is a common side effect of this antibiotics), there is a chance that pills could have got expelled before complete absorption and then the pills may fail to offer protection from the pregnancy.
I hope this helps you.
Dr. Nishikant Shrotri