BFF is pregnant and scared of miscarrying

My best friend got a +HPT on Tuesday and has been faintly bleeding brown since then and cramping. They checked her levels Tues and Fri and they went from 3800 to 2700. Is she going to have a miscarriage!? The nurses can't tell how far along she is but she has an ultrasound on Mon. I just want to give her as much support as possible.