Hai mama! 17 weeks pa lagi, memang placenta boleh gerak naik, so don't worry too much yet, a lot of mums I know had the same situation and it sorted itself out by the third trimester. Best thing is just follow up with your doctor at the next scan to monitor, tapi in the meantime make sure rest enough, avoid heavy lifting, and jangan stress sangat (which I know easier said than done!). If you're worried, minta je your gynae for more detailed explanation pasal position dia sekarang and what to expect next scan.