Nervous & Anxious

Hi ladies, I am 7 weeks & 5 days with my first. I feel like my symptoms are a rollercoaster from each day to the next. One day I feel awful & the next day I feel fine. It's making me feel so nervous that something is wrong. I go for my ultrasound next Thursday, but I'm so anxious, nervous, & scared that the doctor will say something is wrong. Any suggestions on how to ease this anxiety?