Hey Paige! I’m 28 weeks along and also have an anterior placenta. I’d say trust your gut feeling but from my experience, the little one changes position and depending on that the movements can be more noticeable/visible. Have you heard of belly mapping? It was really helpful for me to get an idea of the baby’s position, and figure out approximately where the legs and arms are. Just search belly mapping on YouTube, it’s fun and can put your mind at ease.
Maybe the baby has moved to a different area and you feel the movements less? I'm 26 weeks as well and have an anterior placenta and some days the movement is stronger, other days not so much. You can also try having something sweet and then sitting on your left side, or back, that helped me feel movements better. My midwife said it's not really relevant before 28 weeks but if you are concerned definitely give them a call, each baby is different and you know best what is normal to you.