I am 15 weeks and 5 days pregnant. I been feeling pressure in my lower abdomen. (not cramping) is that normal? Is it my uterus stretching?

Growing pains. If the pressure is not severe, it is likely due to the increasing weight of your uterus as it grows. This is normal and no cause for alarm. Call your OB for eval if tylenol (acetaminophen) and warm baths don't bring relief.