Baby Not Moving

I am 23w4d and starting the beginning of week 18 I could feel the baby move and kick. Last week they were so strong I could see my belly move, but usually she kicked lower towards my abdomen. Yesterday and today I have no felt her kick or move at all. Not even when I drink cold water, or lay down. I do have a heart doppler and was able to find her heartbeat late last night but I'm just wondering if this is normal? I feel very worried and wondering if I should call my doctor.