Bad days

Sometimes I have bad days. Where I get real depressed and sad over not being able to get pregnant. I start to feel like I'm just being sensitive and even feel guilty for feeling upset. Everyone around me has children, including my Bf. So they don't really understand my sadness, often times it makes me feel like I'm just feeling sorry for myself. I can't help it though, sometimes just seeing babies and families brings tears to my eyes. Is this normal? Does anyone else go through this?