1st PT positive; 2nd PT negative

hello, ask ko lang po delayed na po ako ng 6 days, did a test knina 8am 1st urine and it was positive. ngpa blood serim ako agad same day, waiting for the result and then paguwe ko ng test ako ulit with diff brand ng PT and it was negative. signs and symptoms are same with mag kkperiod ako so nkkconfuse but I have a regular mens cycle.