PCOS and late positives?

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I just read online that PCOS (which there's been talk of me possibly having) can cause negative urine and blood tests up until 3-6 months pregnant. My question is, does anyone know how accurate that is? I keep getting either VVFL or negatives on urine tests and I've had two negative blood tests, but my body is giving me almost every single pregnancy symptom. What gives?