I'm going to start feeling like I'm losing it from all this stress.…

I'm going to start feeling like I'm losing it from all this stress. Yesterday we had sex, and today my little one is very quiet. I practically don't feel her at all. Even now, in the evening, especially before bed, she starts moving around, but today there's silence both day and night. What should I do? Maybe I should go for an ultrasound tomorrow.