Terrified

I keep having this recurring fear that I’m having twins and I am literally freaking out. My partner and I were determinedly one and done and then surprise I’m now 7 1/2 weeks pregnant and I’m just beyond terrified that it’s going to be twins when I go to my ultrasound. My symptoms don’t feel any worse than normal if anything this pregnancy has actually been way easier than my 1st was, I’m rarely nauseous just mostly sore chest and headaches but I do feel exhausted literally all day long. Other than that I feel normal and even my nausea is very short lived in the mornings and goes away once I eat. I’ve been trying to research and calm my nerves but I still have 14 days until my ultrasound and I’m literally going crazy with worry

Based on my research I’m only 28, we didn’t use any fertility treatments and twins don’t run on either side of our families so I’m hoping this is just extra nerves from everything being unexpected. It also took over 6 weeks before I even got a dye stealer test so I’m hoping this is just all in my head.

People who have had twins was it super obvious from the start or a complete surprise at the ultrasound?