Am I pregnant?

So my other app pregnancy Plus say I'm 30 days. 4 weeks pregnant and that I'm due July 31st well I had sex with my partner November 4th I was ovulating then the 8th and I wasn't. My period has not started and it was due on the 23. And I haven't tested yet cause I'm scared. But I have been feeling nauseous, craving food, lower back pains, headaches, been really tired. I thought the first two weeks don't count so am I really on 2 weeks? Or actually 4? When can I take a test? and I had this whit stretchy discharge about a week and a half ago what was that for? What do you guys think?