Pregnancy Jealousy

K
My husband and I have now hit our year of trying. It's been really hard for us, me in particular. 
On Sunday my brother announced that he and his wife are expecting their third, which is super great for them, but after putting on a happy face, I went home and cried. 
Then, today while my husband was on his way home from work he told me about a co-worker whose wife is now pregnant, but it happened after 11 months of trying. When he told me, I was just so upset, I couldn't say anything. He's left for the evening to go to school, and I've been crying all night. I am so thrilled for those around me that are expecting, but it is so hard to cope with. 
Am I the only one this happens to?