Pregnant? Due Date? Testing?

We are trying to concieve #2, my last period was Oct 3-6th and I ovulated on the 25th according to my <a href="">period tracker</a> which hasn't been wrong in the year I have had it. My average cycle is 36 days, I took a test 4 days before period and 2 days before period but they were negative, period is set to start in 2 days. When I put in how far along I would be if I was pregnant most sites give me almost 5 weeks and due July 9th but this app gave me almost 4 weeks and due July 16th so I'm confused on when I should test or how far along I would be if I am.