A little help

So I’ll start with a backstory. I started my first period in October 2016, when I was 15 (just). I didn’t have another period for 10 months after that, which I understand is normal, but then they stopped again. In September 2017, I went on the combined pill. In August 2018 I decided to come off the pill and had my withdrawal bleed, but nothing since. I weigh 129 pounds and am 5”8, I am also very active. I had a blood test last week and I am seeing a gynaecologist tomorrow but I just wanted to see if anyone on here had any ideas as to what is wrong with me. Recently I’ve been feeling really tired and cold quite a lot and I never usually get this. I can’t think as to whether there’s anything else I can include but feel free to ask any more questions if I haven’t included something. Thanks if anyone has any answers!!