Closer to my first ultrasound more worried

Katie • 25 years old. Me and my fiancé have a almost 3 year old and TTC #2!!
My first ultrasound is Wednesday the 11, if I'm correct on my dates LMP was Jan 22 so I'm 6w2d due around Oct 29. I find the closer it gets to the ultrasound I find myself getting super worried about something being wrong. All my blood work and repeat blood work has been fine. Doc said no reason to worry. Had some cramping around week 4 but that's gone. No bleeding. Still having nausea and vomiting like I have the whole time. Exhausted all the time still. Nothing has changed but I am still so worried. Any advice to stop worrying so much? This is baby #1.