First things first, the primary reason could be if you have had unprotected sex recently. Even with protected intercourse, there are slim chances that pregnancy might have occurred. Next is a missed period ad; you could also be looking at spotting or cramping during your menstruation cycles. Watch out if your breasts feel tender and sore. They might also appear fuller and feel heavy as compared to normal. Other changes could be fatigue, morning sickness, backache and moodiness in some women. Increased urination appears much later but could be sooner for some. Other hormonal changes include bloating, being more sensitive to some foods or smells, constipation and nasal congestions. The symptoms vary from woman to woman. However, the primary indications are that there can be various changes that make you feel different and sometimes uncomfortable.