20 week ultrasound

Our anatomy scan ultrasound is tomorrow. I know people must go into this with excitement, happy to see their baby and maybe find out the gender. I feel like that's the normal way to feel. I'd be lying if I said I was approaching the appointment with anything other than anxiety and dread. Is it my job, my history of pregnancy loss, or just a pessimistic nature? Probably a combination.
When I think about the appointment, I imagine myself on the table looking at the screen. The room is full of a thick silence while the sonographer takes a closer look. It's obvious there's a problem. From there my imagination brings me to wondering what type of problem? Is it something serious or just concerning for a possible problem? I'm already imagining the follow up level two sonogram or fetal MRI or fetal echo.
With all of that going on in my head, there's not a piece of me that can be excited. I try to tell myself I'm being crazy. I will myself to imagine everything going well, but the daydream where everything goes well seems so much less realistic than the one where there's a problem. The best I can do today is just stop the daydream when I realize its getting started. Just avoid thinking about it.
At least once it's over, there won't be this anxiety to contend with. How long do you think until my head comes up with something else to worry about?