Feeling jealous/rant

I recently found out that my sister is pregnant with baby #2, a surprise and unplanned pregnancy. While I'm happy for her and my brother in law, I have the huge amount of jealousy that is building more and more every day. I am the last girl with 3 of my male cousins in the family of 12 grandkids to have yet to have their own child. I have cousins who have multiple children. I am the fifth oldest of 12 and since I got married in 2012, it has been not only a want but pressure to have my own child. My family is constantly picking at me saying "you're next" or "when you going to pop one out" or "when you going to have one of those" every time it breaks me even more so here lately. I envy my family for having what I want so badly. It takes everything inhave to hold back the tears, I force myself to put on the emotionless face I can and say "I don't know" or "one day" the last few time in have completely given up and said "its not going to happen", I feel like giving up and just have everything removed and be done with it all. I have been to the Dr's and they can't find anything wrong. I cry myself to sleep just about every night and I break down whenever I'm alone. My mom is having "baby fever" since we found out about my younger sister. My mom has said it will happen, and all that come from my mouth and mind is denial. I have days where I'm so depressed and angry intake it it on my DH. And he sometime acts as if the hole baby thing is nothing, I have basically no support from him 90% of the time. I don't want to be jealous of my family for having something wonderful, but it so hard. I while I'm happy for them, deep down I hate them, especially when they rub it in or family makes it worse with the ever so depressing questions. And it does no good talking to them about it, I have a Aunt who like to pick and push button and knows how to get under your skin. Why me? What's wrong with me? I know I'm not alone, and they are other out there who are going through the same things. But I feel so alone.....

I'm sorry for the long rant. I just need to get thing off my chest and release.