Please help a sister, I put to bed last year July, my period return in 28 November being 4 months and 3 weeks after birth, then I have another one in 8 January, another one in 16 February, another one in 21 march and I have not seen another one this month based on my calculation it suppose to be on 22 April but I haven't see it, my question now is what could be the problem.