Further along than the app says

I have a few questions. I took a test at 6 dpo and got a dark line I'm wondering if I'm farther long than I think. This is my 3rd baby and I have been doing keto for 7 months and I'm waking up way early feeling very hungry. I know it's early as of the first day of my last period I am 4 weeks. I will not officially have missed a period until Feb 18th . I feel like I'm feeling more symptoms than I should. My youngest is 18 months which could be some of it. Any thoughts???