Oo normal yan, mama! Sa 12 weeks ang uterus mo ay lumalaki na talaga kaya may heaviness or discomfort ka, lalo na pag maraming ginawa mo sa araw or nakaupo ng matagal. A few of us moms felt the same thing around that time, at sabi ng OB ko it's just the ligaments stretching to accommodate the baby, pero kung sobrang masakit or may cramping na parang labor pains, better to check with your doctor agad lang para safe.