I'm freaking out.

I just found out I'm pregnant with baby #3, we have a 3.5 year old and a 2 year old. It's hard being a parent to toddlers, and we had travel plans for this summer that are going to have to be canceled. I sound so selfish and I should be happy, but I'm not. I cried myself to sleep last night and I feel horrible that I'm not ecstatic like I was with my other two. Is anyone else like me? Please tell me I'm not alone. I know I will love this baby when it becomes more real for me, but for now I'm having issues. Help me.