I’m just wondering


I’m confused the doctor said I’m 7 weeks pregnant he asked me when my last period was and I said 28/11/2018 as that’s when it was and he worked it out over the phone. And said your 7 weeks Wednesday. But he never said how many days cycle am I. Does it matter about how many days cycle? Like mine 37 but I think he’s assumed I’m 28?

Please somebody help me