What Are Side Effects Of Taking Primolut During Pregnancy?

hi i am 17 yrs old..and i saw my period last month, but i can remember the date exactly..i think it was in the middle of the month, i havnt seen my period for this month at all. i tokk a test on friday the 17th of june after having sex the friday of last week, the results showed positive, i took another test on the 18th it still said i was positive.my dr prescribed that i take primolut cause i told him i was pregnant.what are the side effects of taking this pill?..and will it help prevent me from having this baby, like he said?