Trying and trying

My fiancé and I have been trying for a little over a year and nothing. I lay there with my hips up after, he cums as deep inside me as possible, I take vitamins and still nothing. My doctor put me on progesterone because my periods have always been irregular and I would skip a couple months which of course made me think I was pregnant:/ my aunt(moms sister) had uteran cancer so I'm worried I am on my way to developing it. Either that or I can't have children