Finding it hard to hear about my finace brothers daughter from his family

Teri-lyn • 22 mommy to lincoln 05.11.2016 and ttc# 2 !!
My finace brother and his go had a baby back in December and his parents are over the moon excited . When we found out we were pregnant I was so excited to tell his parents we were gonna tell them after our 11 weeks scan but . That vhance never came I miscarried at 6 weeks and 4 days we saw them this weekend and all his mom and dad could do was talk about there grand daughter and how she's smiling and cooing and all this and I just sat there and fought back my tears . Iam hurt and extremely sad . We have to go to easter dinner with his hole family and I have to see his brother his girlfriend and there baby. It's gonna kill me because this depression is getting so bad . I see people on the streets holding there babys or pushing there strollers and my heart brakes . My finace don't understand why iam depressed or why iam taking it so hard he keeps saying we can always have another one which I know we can but it hurts it's hard to have to hear his family talk about this little girl . While iam sitting there grieving my ass off. What do I do . It hurts so much iam falling apart slowly . This depression is effecting my relationship . :'(