Ay, normal yun sa first few weeks ng IUD, lalo na fresh pa lang ang insertion mo at 17 days pa lang si baby, ang katawan mo pa rin talaga nag-aayos from delivery! A few of us had cramping and soreness for weeks after, especially pag mahabang sitting o standing, so don't worry na nabaliwan ka lang ng karanasan ngayong insertion. That said, since medyo struggle ka talaga sa pag-lakad and the pain is pretty consistent kahit umupo ka, better to check with your OB just to make sure everything's good with the placement, hindi lang paranoia, better safe than sorry lalo na baguhan ka pa. Take it easy muna, rest when you can, and paracetamol is your friend para sa cramping if doc approves (esp if breastfeeding ka pa). You'll feel better soon, promise!