What Causes Delayed Periods After The Removal Of Vaginal Ring?

HI I have two kids which are 2 and one and ever since i had my second child in may of 09 i got put on the vaginal ring birth control which made me only have my period of 3days so im no longer on the vaginal ring and i am still having my period 3days at a time but the past two months april and may my period has came about a week late maybe a little longer...its everything okay?