Over 2 weeks late

Monica Briggs

So by my LMC IS 7 WEEKS BUT I think my day of conception would of been later but anyway I keep getting bfn except for 1 that came back with really light line but idk if it was just a FP or what I have PCOS but have had regular period for the last year and had a miscarriage in July I've had lots of symptoms heartburn sickicky feelings frequent urination and such any advice for me BETTER TEST? 88 CENT test from Walmart