Just need some advice..

Let me start off saying in August we will have been trying for 2 years with one miscarriage. I’m on my 5 cycle of clomid and absolutely no luck. My little sister and her bf decided to start a family and 4 months later she told me she was pregnant and not to mention it was on Mother’s Day. I want to be supportive but it’s so hard. I don’t get it. 😭 my husband and I have been married for 2 years, we own our house. Both have amazing jobs making good money. What am I doing to wrong that we can’t start a family? My sister and I used to be close but now we hardly talk, I hate it more then anything but I can’t help it.