i am very early on in the pregnancy however i am in a lot of boob pain and they have gotten about 2sizes while only being 5weeks along. My stomach also feels heavy and when i dont hold it in slightly, it goes from having a line between top and bottom of the tummy then to no line, i am curious as to why this is and due to twins running in my family, im worried it will also be twins as i am only 21. i have no other signs other than slight sharp back pain occasionally.