TTC and scared

4th month trying! What is happening and can someone explain in detail why I'm not getting pregnant? Does it really take 1 year for a healthy couple. I have 1 child who I got pregnant with almost immediately after stopping birth control and now have waited until Im more than ready for #2 but it's just not happening and the disappointment is really hurting. Let me add that my periods are extremely regular and normal in length. Im healthy, I have a glass of wine on occasion and drink only 1 cup of coffee a day. Explaining to my son why he doesn't have a sibling breaks why heart.... please tell me there's hope!!! I need hope and to hold on and not lose my shit just yet.