Less fetal movement, 33 weeks

I'm 33 weeks 4 days and starting at 32 weeks 6 days my daughter's movements have slowed down. I still count kicks twice a day and get to 10 usually in 2-3 min but it worries me. She was extremely active weeks 28-32 and now she seems to only be active after meals and not for very long. Not only do I feel less movement, but they also seem weaker. I've been debating about going to the ER and getting her checked on but I have an ultrasound scheduled for Monday. I really can't stop thinking about her and her wellbeing but I also tend to be a worry wart. Should I just make the trip or wait it out until Monday? Help fellow mommies to be...