oldest is almost 11....

okay so my daughter will be 11 in April. I am currently pregnant 5 weeks 2 days. I just had a miscarriage in the beginning of February. my daughter doesn't know that we are expecting. does anyone else have kiddos with that big of an age gap? I mean I have had 4 miscarriages and then of course one love birth. I'm just super worried that my daughter will feel like we are trying to replace her. my husband whom my daughter call's dad is not her bio so I worry about that too... I'm trying to stay as calm as possible but some days its all I can think Bout because I love her so much. she is the product of a rape so she grew up without a father figure for the first 4 1/2 years.... I'm just worried about her. anyone else have quite a bit older kids and pregnant now or with an infant? how did the older kids do?