I have an anterior placenta too. Mine is on my right though & it helps knowing where it's at... You can try belly mapping to figure out baby's position maybe the legs are behind the placenta so all you feel are little fingers?
I would drink some juice get on your side for 1-2 hours & see how much movement you feel, then maybe call the doctor if you are worried. That's what my midwife told me to do if I was ever worried about.movement. She gave me kick count instructions that I'm sure you can find online.
My dr told me that because i have an anterior placenta that I may not feel much movement at times. But I would call your doctors office with your concerns.