Welcome to HealthcareMagic forum.
I feel this is a menstrual imbalance due to hormonal
changes , you must see a gynecologist as many of your cycles have been irregular, you will need an examination and some blood tests with a scan to find out the cause . Depending on the same , you will be put on medicines to regularize the cycles .
I hope your weight is fine and not obese
. make sure you do good physical activity daily
Wish you good health