False positives are rare but false negatives are common. HCG levels will fluctuate throughout the day and as a result of hydration levels which can effect ability to detect it during early pregnancy when levels are still low.
Take a digital test in a few days using first morning urine. I suspect you are pregnant and the test will conclude this.
your urine was probably diluted more the 2nd time, As spade said take a digi tomorrow that will clear it all up!
i think take a blood test that will me more accurate to know are you pregnant or not
.Good luck
Took another test today and it said pregnant but have dr apt on friday to be sure