pregnancy and menopause

I have just turned 50 and have not had a proper period for nearly 12 months, except for a slight bleed a couple of months ago. I have menopausal symptoms (flushes, forgetfulness, irritability etc.). I have recently had unprotected sex, and have been told by a friend that I run the risk of pregnancy, although I don't think I do as I believe I'm definitely menopausal. Any thoughts/comments please.