Please dont judge

I'm pregnant with my second, my first is 14 months and im 14 weeks, for some reason I'm not so excited like I was with my first, I'm in a great relationship and have a happy and loving family that we have and are creating, but sometimes I think to my self am I doing the right thing having another so quickly and then I get down and just think twice about what I'm doing, I got postnatal depression after my daughter and got help straight away because I didn't want my partner or daughter getting dragged down the path I was experiencing as they mean the world to me but could this be a phase? Is this normal? I feel bad because I love this baby already but got no excitement towards him/her arriving am I a bad mum :(