Less movement and slower heart rate?

I bought an at home Doppler to ease my mind, and I've had it for over a week now. My little girls heart rate is always 135-140bpm, and it never fails. It usually sounds like a fast train. Just yesterday (after getting in a huge fight with my brother and his wife the night before because they started saying awful things to my husband and I) her movements are barely noticeable, and I only get a few good movements, but not her normal pattern. I can't poke her, or even drink something and wait and see because she won't budge. She just isn't responding to the usual things she responds to. She isn't moving as much at night which she always does.

Could she just be growing/sleeping? I know that if she's not being active, her heart rate might be lower, and movement would obviously be less. I'm almost 28 weeks. Should I call my doctor, or just keep an eye on it with Doppler + movement count?