Hii... irregular menstrual cycle is quiet common in PCOS. Weight gain,hair fall and acne are typical features of PCOS. There is no permanent treatment for PCOS as it is not a disease but it's a cluster of some features due to hormonal disturbances. Lifestyle modification is the best option for controlling severity. It includes diet restriction to 1200cal- for this u can do calorie counting by installing any app (eg,healthify me), and doing exercises like brisk walking/skipping(diet +exercise works better,than either alone- so no cheating) . Atleast 5% -10% of weight loss will correct hormonal changes and regularise ur cycles. If you had sex then it's always better to rule out pregnancy first. So better u consult a doctor nearby who will evaluate you in detail and prescribe you accordingly.
Next Steps
Undergo urine
pregnancy test first. Then u can consult a gynaecologist who will do a basal scan and give medicines for withdrawal periods and suggest you on haemorrhagic cyst depending on its size.
Health Tips
limit rice and rice products - as they are carbohydrates and u will gain weight quickly. Take plenty of fruits and vegetables. U can replace rice with either quinoa or millets.