Talk to Gynecologist on Medicine Advise

I went to doctor for the problem of irregular periods after marriage ....she suggested me a pelvic ultrasound which is clear having no mass in reproductive system but free floating echoes appear in urinary bladder showing cystitis.........and Said" k yeh to normal he itna sub ko hta"please tell me she said correctly?secondly this month I have my periods 2 days before my due date of previous month(without any medication)....but I still find a little blood just when I urinate ......this is happeing with me from last 3 months and after 2 -3 days of this spotting I get my regular menstrual flow for 5-6 days.Dcotor suggested me Duphaston(dydrogesterone)10mg to use for 3 months........I want to ask that should I use this medicine? (please advise me the dosage also)or should I wait for natural periods regularity for few more months without using medicine as I m also trying to lose my weight from last 3 months and I lost 5 kg up till now I m attaching my ultrasound report also