Pregnant or not?

I'm not sure if I'm pregnant. If I am, I'm 3 weeks along. I don't have obvious nausea, but it feels kind of vague. I also have cramps in my lower abdomen and am gassy. Some sebum also came out of my nipple. Otherwise, there aren't many changes, except that they're extremely sensitive. I've also been freezing cold yesterday and today. Is this due to the weather or am I pregnant?

I should get my period again on November 13th, hopefully.
Are these symptoms an indication that I'm pregnant? Or is it just a mild flu, since I also had severe diarrhea? I also drank a lot of coffee all at once (my hands were shaking badly, I was sweating, and I thought I'd faint when I stood up), and my period is due soon anyway.

I also had severe itching in my vagina, a burning sensation, and white discharge. I think it's due to the polyamide underwear I wore for the first time ever. I also have a lot of stress, probably chronic. So I thought the extra fatigue might also be due to candida.