this forum has many examples of changes in cycles. they all settle down into normal or better. menopause is practically nonexistent, those who have gone through menopause once again have a few periods before settling into a symptom-free post menses, comments like "my periods are now the way they were when i was 16" have been heard repeatedly, etc, etc.
work through adjustment periods by maintaining adequate Iodine intake. 100mg is a minimum.