No way, you are not crazy. It's tough being so close to what we may never have. It sounds like you are preparing for the worst (of course you would be happy for your sister, but it will hurt). I don't really have any advice other than to breathe, focus on the present moment, and keep doing everything you can to build your own family.
You are not crazy. We have all been there, and with your miscarriage it makes sense completely. Hugs.

This is a topic i have been on the recieving end of....
You are not nuts for starters and its your perfect natural woman instinct to be a little jelouse of your sister more so than your friends if she gets pregnant, - firstly you are the big sister and its supose to happen to your first, secondly all your family will be rallying around the new baby if she had one and you will wish that was happening to you ...

If your sister knows about your stuggle - and is anything like a person i know, she will be feeling your anguish also, and is probably going through it with you hoping and praying that you one day bare a child... seriously for your relationship with her be happy if it happens and know that you will be the greatest aunt in the world, that would be your job there, to be an aunt not a mother...
and for the record your not selfish - your a woman who wants something very badly and will stop at nothing to get it - but that doesnt mean destroying a life time relationship with her because she is able to produce naturally - its a really hard one to control and to answer... but im sure she cares for you as much as its obvious you care about her xxxx

You are not going nuts, I told my best friends that if he got a girl pregnant I would punch him and never talk to him again. He is single.

You are not nuts. I have been having the same thoughts about my sister-in-law. I'm pretty sure her and her boyfriend will get engaged soon and all I can keep thinking is "Watch, she'll be pregnant before me". I've even made this comment to my husband. I hate that I feel this way and I really just want the best for her. I've been trying to think if she does get pregnant first then she deserves it. She is older than me and has wanted children for a while too!

You're not crazy. It's something all women dealing with IF feel. Sometimes, one person's news is just the final straw. You'd feel bad if you couldn't be supportive of your sister, but at the same time, you wouldn't be wholly happy and supportive as you could be if you went down and "faked" it and you'd feel bad about that too. It's complicated and frustrating. You may find your family totally understanding, or you may find that they think you're a jerk, but regardless, you have to do what's best for you, whether that's avoidance, or not discussing babies, or whatever. When you're in a more peaceful state of mind, you'll know, and you'll be ready to face it (if it happens). There's no easy procedure to make IF easy to deal with in the face of someone else's happiness. It seems like it's either "Swallow down my own misery for their sake" or "hurt people by hiding/avoiding/not speaking so I can preserve my own sanity." Until you're on the other side of that grief train, it's a game of self-preservation. Hang in there!

You are not crazy at all. I am going through the SAME exact thing. My younger sister quit using protection last year but since her cycle is irregular (sometimes doesn't even have a cycle) then conceiving was a LONG shot. But she got a new job, get EXCELLENT insurance, to the point where they will pay all IF, even a large portion of IVF if needed, so I'm sure if she's aggressive with her treatments, she'll be pregnant by the end of the year. I honestly don't know how to handle it, I dread every phone call I get from her. I want to say I'll be happy and I'm sure deep down I will be but it's going to be really really hard. You are not bad or crazy, you are a woman whose been dealing with an injustice and you've had enough.