Worried about my fertility with PCOS and IUD

IUDs don't cause sterilisation, there are plenty of reputable, peer reviewed studies and information available, your professor should keep their opinions to themselves. IUDs help many, many people with PCOS be able to have a much more comfortable quality of life, as I'm sure you're well aware. I personally have many ovarian cysts and I have gone for over a year at times without a period, I have conceived naturally (with a partner who had their own fertility issues) 8 times, and carried to term 4 times, that is without any kind of intervention and in my case with additional odds stacked against me. I was of the 'if it happens, it happens' school of thought, and not actively preventing though not actively trying. Something that seriously can affect the odds is stress. I understand though, I was told very young by my doctor that I would never be able to have children due to PCOS. Also to add, adoption as a single parent is entirely possible, as is using a surrogate parent. Any parent could become single, my advice would be to plan as a single parent if you have fertility issues, and welcome a perfect partner onboard the plan if it happens but don't deny yourself a much loved baby if they don't turn up in time. Surround yourself with love and support from family (inc. found) and friends.