Unintentional pressure

So my best friend who is like my sister just found out she's pregnant. They were trying for like 3 months. My husband and I have been trying for a year and a half. Don't get me wrong, I am soooooo happy for them, but now I feel like it's putting more pressure on my mind. Like I'm supposed to be trying to relax and not think about trying but how can I not? My next fertile week is the same week (obviously different years lol) that we conceived our son and i feel like that is gonna be my lucky month but now i can't stop thinking about trying and when to try. I can't help but think that i have to get pregnant soon so our babies can be close like we are (we're 6 months apart). But i know it won't happen as long as I'm thinking like this. How to i stop thinking about all of this? Last month i ovulated late and completely didn't realize it and wasn't thinking about trying and we managed to BD a few times at the right times so i swore last month was my month and it wasn't. Idk how to relax and stop stressing! :(