When was your period in april?
Saying you usually start your period btween the 2-6 each month is really inaccurate.
You see day 1 of your cycle is the first day that you bleed.
(the number of days you bleed is likely to vary).
Therefore if you had a 28 day cycle you would have 13 periods in a year.
As an example of a 28 day cycle lets say your period began on 1 march - you would get
2 periods in march because your next one would be on the 29 march.
It sounds like you just had a light period but I would advise taking a test just to know for sure and to put your mind at rest.