Alah, itu memang normal la, especially bila you're pregnant, hormones and blood volume you naik, so heart palpitations memang common! A few of my mum friends experienced the same around that stage, siap takut-takut hari-hari haha. But since you're noticing it agak kuat and it's making you worried, best to mention it to your doc at your next checkup or even call the clinic je, just for peace of mind, they can confirm everything's good with you and baby. Jangan stress sangat k, normally fine je, but always better safe than sorry when you're pregnant!