I have 3 different apps. They all told me I ovulated around the same time, which I did but, 1 app says period starts the 30th, another says the 31st, & the other says the 8th.. not sure which one to follow. My average cycle is 21 days. I took a test on the 24th it was negative, & took another one today (28th), also negative, but I don't have any period symptoms like I usually do? Although, I did wake up at 3am to throw up. I've had Nausea, Hot Flashes & Headaches, that's about it. I guess I'm just confused..