How should I explain this to the doctor?

I am 42 and I have only had two periods in five months, one which was quite spotty and one now which is very, very heavy. I have had blood tests and my hormone levels look normal and it is not the start of the menopause, I am not pregnant. I am aneamic and I have also put on a little weight in the past year so I wondered if any of that could make it worse. Also when my partner and I were having the other night it was really painful on my left side, I hadnt had a period for two months but straight away after that my period came. I have a doctors appointment in two hours and I dont know how to explain and I am a little embarrased about how to say it hurt whilst having ! I am quite a sensitive and shy person. Please help. Thank you.