Period in 15 days. On above questions?

Hi Doctors, I recently(2 months)got married with Jyothi and my wife got period on 23rd April and last for 4days as per her monthly cycle. But again this month May 8th she got period 2nd time with in 15 days but it last only 1 day. - 8th May morning we had bike trip for 30 km. - 6th may and 7th may she ate pappaya fruit. -No stress. - May 8th morning time blood came like periods first day but evening onwards she did not blood and only few drops while going to urine. - we had unprotected sex on May 3,4,5 and 6. - This is 2nd time she got period with in 15 days like this , one is before marriage when she went to long trip and 2nd time on May 8th. Question: Why she got 2nd period with in 15days? Is she pregnant? Is there any medical problems ? We are not ready for pregnant at this time? Could you please check and advise on above questions?