second infertility

Is anyone else going though this? so, I do have a child, he's 5 years old. My husband and I have been trying to have a baby together now for a year and a half. The children we have are from past relationships and we would love to have a baby together but, alas nothing has happened, just a lot of upset each month that goes by and no positive results. Why was it so easy for my first and now so difficult? It's all so heartbreaking, and I'm so scared that I won't get to experience the joy of being pregnant again. 😢😢