There are many signs that indicate pregnancy. Some are subtle, while same are glaringly obvious. Some are easy to confuse with the sensations many women get every month when they are expecting their period, or with the symptoms of a common cold or flu. Perhaps no "symptom" of pregnancy is quite as unique as this one. Many newly pregnant women instinctively "know" they are pregnant. This feeling has little to do with any of the other symptoms of early pregnancy, and it isn't uncommon to just "feel" pregnant even before your period is due.
"Hey, I think I am pregnant" is a feeling that you can encounter even if you are not experiencing any morning sickness, don't have tender breasts, and have not even missed a period yet. It is something that can strike seemingly out of nowhere, even if you don't have a clue when your menstruation should be starting. Are you suddenly overcome by this feeling? It happens to many women, and their instincts are proven right a lot of the time. If this description fits you, take your feelings seriously and get a pregnancy test. Of course, there is nothing scientific about this pregnancy sign. Women who have been trying to conceive for a while might think that this is a feeling they experience every month, and that it simply means they hope they succeeded this time.
But when you are pregnant and simply feel it, it is something that you will be able to distinguish from the feeling of just hoping you might have conceived. Feeling that you are pregnant is, arguably, just as much of an indication that you are expecting as any of the other, more objective signs of pregnancy. This does not happen to every woman, and of course it is entirely possible to be pregnant and not have that "knowing feeling". If you do get it, don't ignore it, though. We are working on a comprehensive list of any and all pregnancy signs. It's currently a work in progress, but please check the page if you are wondering about other symptoms of pregnancy.