I can completely understand that. Having children is a big responsibility (aside from the fact that they are great) and sharing that responsibility with a kind, loving partner is a good thing to have and a totally reasonable thing to want/expect.
First of all, if I haven't said it before, I think that is such a great decision you made to have the second baby on your own.
As dandylion mentioned, hormones are no doubt playing a part in your feelings right now. That's to be expected but still, I'm sure it's hard.
All the work you did to set yourself up. Think about how well that is serving you right now. You have the ability to not only look after yourself but your Daughter and this new little baby, that's a HUGE accomplishment. You should be so proud of yourself, really. What a wonderful little family you will have, the three of you.
Now, someday, there is probably going to be a man who will enter this picture and you will be ready at that point and not before. I'm sure it seems impossible or really undesirable right now, again, totally understandable, but you probably will not always feel this way.
I wish we could all throw you a baby shower!