PCOS Metformin Dosage

I am 22 year old female, who has PCOS and am also obese (89kg and 163cm). I went to a gynaecologist last year, and I was prescribed Metformin 500mg (1 tablet every night) and oral contraceptive ‘Loette’ (21 tablet strip, each contains 20 mcg Ethinyl Estradiol and 100 mcg Levonogestrel). I was 90 kg when I started taking these medicines and by the time I had my net appointment with the doctor (3 months later) I have lost about 3kgs, and my other symptoms of PCOS (fatigue, hirsutism, and hair loss) had some improvements too. But after the 3 months, my weight slowly started to gain back, along with all the improvements I had slowly vanished too, and now I’m back where I started again. Basically the Metformin 500mg per day has not been changed for the past 1 year, and I think it might be the reason why the changes did not stay. I am also 100% sure there were no major lifestyle changes that happened during this 1 year. My lifestyle is naturally very healthy (little to no junk/fast food, little to no sweets/sodas/cakes, 30 minutes yoga 6 days per week, and around 7 hours of sleep every night). I lost weight and gained the weight back when there was no major/minor lifestyle change in my daily life. So until today I have been taking Metformin 500mg, 1 tablet per day, which I would like to increase to 2 tablets per day. I would like to know, is it okay for me to do it (I did not have any adverse/side effects when I started taking it newly btw). Is it advisable? What should I look out for? And considering I am taking Glucophage XR 500 mg, shall I take 1 in the morning and 1 at night, or can I take both at night?