What is the chance I have secondary infertility?

Hi doctor,

I just wanted to know my chances of having secondary infertility. When 15, I was sexually assaulted, which resulted in pregnancy and late-term abortion. At 18, I fell pregnant with my son. I had an easy pregnancy with no complications. Last year, at 28 weeks, I went into early labor, which stopped until 29 weeks, and his heart rate started dropping and not picking back up, and I started bleeding. They delivered him at 29 weeks via emergency C-section. During the healing process, I had a hematoma and a large infection right on top of each other, and after two weeks of not being able to walk, only being in a wheelchair, my healed scar ripped open, and blood and pus were leaking for days. I have since last year not used protection with my partner, and since the end of the year, I have been tracking my cycle and making sure we had sex days before, during, and after my ovulation. I guess I want to know when I should go to the doctors, how secondary infertility is diagnosed and what you think about my situation. Also, periods have been a lot heavier since the birth of my son, more painful, and large clots. Before his birth, my periods were very light, lasted three days, and I had no pain or clots.