subchorionic hemorrhage?

well I should be about 7wks and 4 days today, but I visited the ER Friday because I was having pink spotting and bad cramps on my right side. I had a transvaginal u/s and a abdominal u/s, baby was fine and growing well with a 125bpm heartbeat. but I was told that I had a small subchorionic hemorrhage that was only about a cm. doctor told me that they usually dissolve by the end of the first trimester when they're this tiny, and lots of women go on to have healthy and normal pregnancies. I was just wondering, has any other ladies had this problem and how did it turn out? this is my very first pregnancy at age 17 and I am just very scared to miscarry. can anyone tell me anything about this? my EDD is September 18th and I go for another ultrasound Monday at 1pm :)