Hello. My Period Started March 12 And Lasted For 10

Hello. My period started march 12 and lasted for 10 days. the first 4 days were just dark brown light bleeding, then for 2-3 days it was the normal red heavy bleeding, and then 2-3 days it was dark brown light bleeding again. then after that stopped ive had light cramping, lil bit of backache, and breasts are lil sore. could I be pregnant? when should I take a pregnancy test?