Bleeding during pregnancy

Elizabeth
Hello ladies so I am 12 weeks pregnant according to my last menstrual period and the last time I went to the ER I was told I was smaller about 10 weeks . 2days ago I went to the ER because I randomly released a quarter size clot and started bleeding. The baby had a heart beat and there was no bleeding in the placenta so I was I tricked to rest . Been in bed for 2 days the doctor told me I'm 12 to 14 weeks this time or it's a big baby . I don't know why the bleeding started u had no pain or discomfort it has stopped now but I'm really nervous I was told there's a 50 50 chance with women this happens too anyone experienced something similar ?