So the first time i left it in for 4 weeks and put a new one in right after. Thats what my doctor said to do. But then after 3 weeks with the new one in, i started to bleed so i took it out and has my period. Then after a week, i put a new one in and the blood stopped. Now after 3 weeks i took it out on thursday (its now sunday) and i still havent got my period. Could i be pregnant?