What should I do about my heavy and painful periods at 16 with possible PCOS?

I am a 16-year-old girl seeking advice regarding my menstrual health. Menstrual history: - I got my first period at the age of 12. - My periods have been irregular since the beginning and usually occur every 40–60 days. - Sometimes I have only spotting, while at other times the bleeding is very heavy. Current problem: - My current period started after a gap of 51 days. - This is the heaviest and most painful period I have ever experienced. - The bleeding is bright red with clots. - A period panty that normally lasts me about 24 hours is lasting only 4–6 hours during this cycle. - My pain reached 8–8.5/10. After taking a pain medicine, I got relief for about 4 hours, but the pain returned. - The pain is mainly in my lower abdomen and sometimes radiates to my left lower back. - I have also felt weak and mildly dizzy while standing. Other symptoms over the past 4+ years: - Acne. - Facial hair growth. - Hair loss from my scalp. - Weight gain. - I often experience period-like cramps around the time my period is due, but sometimes the bleeding does not start. Past medical history: - PCOS was suspected about 2 years ago, but my ultrasound was reported as normal. - I have hypothyroidism, but my recent thyroid tests are normal. - In the past, my prolactin level was mildly elevated, possibly due to hypothyroidism. - My hemoglobin is normal. Current details: - Age: 16 years - Height: 166 cm (5 ft 5½ in) - Weight: 68 kg Could you please advise: 1. Does this history suggest PCOS? 2. Could there be another condition, such as endometriosis or another hormonal problem? 3. What tests or investigations would you recommend? 4. Should I be concerned about the heavy bleeding and severe pain during this period? 5. What treatment would you suggest for both my irregular periods and painful/heavy periods? Thank you.