My period calender said I was fertile and that

Patient: My period calender said I was fertile . and that night I was intimate without protection . this was Feb. 27 . i have been cramping on and off since then and haven’t sharp headaches that last two seconds. Then today I spotted drops of blood. And now I feel uncomfortable. My period isn’t suppose to start til the 15th. Am I able to take a pregnancy test already ? Or do I wait

Doctor: