Is it safe to take morning after pill 3 times in one month can i get pregnant if i have sex on the last day of my period? 28day cycle

No and yes: No because morning after pills use an absurd amount of synthetic hormones and chemicals to knock you uterus into not getting pregnant, and 3 times a month will simply not work well anyway - the failure rate for that pill increases dramatically if similar pills are used within a few weeks. Yes because if you ovulated on day 14 of the cycle your egg is fertile for up to 10 days and u could miscount.

Risk of pregnancy: Even with a regular cycle, you cannot predict early ovulation. The last day of your period? Not safe. Anyone who is needing 3 doses of Plan B/morning after pill, NEEDS a reliable birth control method. Period. See your doctor or a family planning clinic.