Baby movement?

I’m 21w3d now. Ever since about 20 weeks I have been feeling the baby move. The past 3 days baby hasn’t been as active as normal. I always just feel her when I’m sitting down relaxing. I’m a hairstylist so this week has been crazy and I haven’t did a lot of sitting other than late in the evening. But even then I have barely felt her. Is this normal for baby not to be as active some days at this stage in pregnancy? I know baby is still pretty small. I have felt her a couple times the past 30 minutes so I’m guessing everything is okay. Just wanted to hear other ladies experiences :)