Kickssss

Hello. Im a first time mom, im 30 weeks pregnant. Im supposed to count every movement of the baby, right mommies? I dont know but i dont always feel the baby kick. She moves sometimes. Like today, i felt her move during lunchtime only. And sometimes, i get a twitching or spasming feeling in my belly. I dont know if its the baby or just the muscle.. Should i be worried?