Need to know why i feel so nauseous...

Ana

So i had unprotected sex when visiting my boyfriend while on my period on March 10th which was also the day i started my period. I took the Plan B on the 11th and bled until around the 20th (which i knew was normal for taking plan b) and i got on birth control for the first time ever on the 21st. And started taking it right away everday. My boyfriend comes home and surprises me on March 30th and we had unprotected sex on the 31st and April 2nd/3rd. I had been on birth control for a consistent 9/10 days and my doctor said it was safe after 7 days. It is now April 12 and i haven’t gotten my period and i started taking my placebo pills on the 11th. I have been feeling nauseous all day today and headaches and stomach aches. I need help i dont know whats going on.

Thank you for any help