Baby Movements

So I started feeling my baby move pretty early on. I think I was around 14 weeks when I felt my  first flutter. I am now 21 weeks and the feeling of movements have slowly increased. For the past 2-3 weeks I have felt her like crazy. Especially after dinner until I go to bed, it seems like she is moving nonstop. However, for the past 4 days or so, the feeling of movements have leased a lot. I feel her still but not nearly as much as I did. Is this normal? If so, why the decrease in movement? My husband and I have been having sex more the past week... does that have anything to do with it? I have my anatomy scan in a week.... is this pretty urgent and do I need to call my doctor now or can it wait a week?