Dear Madam, I have gone through your elaborate detailed nicely narrated history. The very fact that you have missed 5 pills during last cycle makes you quite vulnerable to pregnancy after unprotected sex. You had unprotected intercourse on day 21 of the cycle. Presuming your cycle to be of 28 days, the day of ovulation is da 14. Egg is alive for 24 hours and the sperms are active for 72 hours. Hence the fertile period will be from day 10 to day 18. However, missing of the pills may disturb this date also. Moreover, you have completely missed your period. We always try to diagnose/rule out pregnancy first after missing a period. So unless and until proved otherwise, let us presume it to be due to pregnancy. The other symptoms of pregnancy are nausea & vomiting, frequent urination and breast signs (engorgement, tenderness, discolouration of nipples and areola with widening of areola and secretions). However, all these appear about a week to 10 days after missed period. Hence even though you have tremendous nausea and vomiting, it may be basically due to some other cause. Particularly the facts that your pain in abdomen, nausea and vomiting started before you missed your period and now it is associated with intermittent constipation and diarrhea suggests the possibility of amoebic dysentery. Please get your stools examined. If it is amoebiasis, you will have to undergo its treatment by Metronidazole with proton pump inhibitor to take care of gastritis you are having. Of course before undergoing any treatment, you will have to confirm the status of your pregnancy. Madam, though urine pregnancy tests and ultrasonography give reliable reports only after 8-10 days of missed period, Beta hCG tests can detect the pregnancy within a couple of days of missed period. You may go for that. Please get your pregnancy status detected. Report to the Obstetrician for further management of pregnancy and gastro-intestinal problem. I hope you will take the advice seriously.