There are many factors that can cause your cycle to go wonky or disappear completely.
Did something happen in March that caused your cycle to stop?
What's your food intake like? Are you dieting? Are you eating a very low carb diet? Are you eating a very low calorie diet?
What's your exercise like?
How's your sleep?
What are your stress levels like?
Have you had your hormone levels checked? (LH, FSH, progestrone, estrogen)