Issues with pregnancy after 1st baby

We had no problem falling pregnant with our son. We got pregnant right away, no complications during pregnancy, we did have a planned c section due to him being breeched. He is now 2.5 years old. Since then we had an early miscarriage at 5 weeks last September (it was unplanned) then planned and fell pregnant the next month after with identical twin boys. We had a TFMR due to a rare diagnosis and quality of life this March. They thought I had a chemical pregnancy 2 months after which was not planned. Then just 2 weeks ago I had a spontaneous miscarriage at exactly 9 weeks which was a planned pregnancy. So my question is, after having a healthy pregnancy did you have issues staying pregnant while trying to have a second baby? I know some people have secondary infertility, but for me I get pregnant but have trouble keeping it again.