Confused

When I first input the first day of my last period on <a href="https://play.google.com/store/apps/details?id=com.glow.android.nurture">nurture</a> (Jan. 13) it said I was 2 weeks pregnant and due Nov 1st. That didn't seem right because I felt like I was having more symptoms than 2 weeks. (Nausea, hunger,light cramping, extreme break out, and breaking down and crying over nothing, bloating) I went from eating once or twice a day to minimum of 4 times a day. So I did a calculator online and it said Oct. 20 so I went in and changed it and now it says I'm 4 weeks. I know going to the doctor is how I'll find out how far I really am but which do you think is right? My period in Jan was also normal the first day and a half and light spotting the rest.