Did I convince myself or is it a real feeling?

I’ve basically convinced myself I’m having twins. First off my grandmother told me a few months before I got pregnant that I would be having twin girls. I’m 10 weeks and my first ultrasound is next Friday. I haven’t been that sick mostly just afternoon nausea and exhaustion. This is my first pregnancy so I have nothing to compare it to. But I keep telling my husband it’s twins and I even had a dream I had a boy and was waiting to deliver the second baby. So I’m not sure if this is because I want twins so bad or if it’s a genuine feeling that I’m having twins. Am I nuts?!