You can try Dr Chris Ng. He's also private--his clinic is in Camden Med. He's been my gynae since I was in college and he's really nice and professional.
Have you checked with your gynae? Before I didn't have any periods for 6 months and visited my gynae. He did physical check and ultrasound but said I only have hormonal imbalance caused by stress. He just gave me pills and my period came after. I also decided to be healthier, eat better, sleep...