No Period, No BFP

Has anyone ever been 3 days late on their period and gotten all negative tests (including first response) and still ended up pregnant?! I’m now not sure my ovulation was right, maybe it was later than I thought and that’s why I haven’t gotten a positive test yet?! Perhaps my period isn’t late at all and I just miscalculated and all the symptoms I’m having are just because I want to think I am pregnant still somehow?! (Nausea, headaches, very fatigue, thick milky like vaginal mucus too) I am very stressed because family members aren’t doing well. Please help! 😢💔