My DH and I have been struggling to conceive for over 3 years now. The years have been really emotionally draining and I'm saddened to say my mental health has plummeted during these struggles 
My lovely younger sister and BIL told us that she would like to start trying for their first baby. They explained their reasonings for telling us, so it isn't so much of a shock etc if / when it happens and so we have time to process things. They were lovely and really sensitive about it.. but it still really hurt. I tried to paste on a happy smile and encouraging words but deep down it felt like my own life was shattering.
Anyway, a month later and yesterday she found out they're expecting. It happened to fast I'm shocked. I'm happy for them, of course I am. And excited deep down, but I feel so sad. I also feel terribly guilty for feeling this way. This isn't my news and isn't about me, so why do I feel so sad. I tried my best again to smile and get excited for them, but my heart just hurts.
My DH has last week, been advised that he has a low sperm count so we now know more about why we have been struggling to conceive, and we have been looking into our options but it's all so costly. I just wish for nothing more than our own baby. It's all either of us want 😔 it's just so hard.
So, I guess.. AIBU to feel so sad, even though somewhere inside I'm elated for them? I feel so selfish and awful.