You know, I did bring it up in my last post (when I mentioned PND, that stands for post-natal depression), and I do tend to agree with the other ladies who suggest seeing your doctor about it.
PND can cause feelings of inadequacy as a mom, feelings of "not deserving" your child, a lack of connection between a mother and child, and guilt. Honey, please go talk to someone. They can help you work through these feelings, and perhaps even start you on some temporary medication to sort things out a bit faster. If you get help sooner, you will better bond with your daughter, and not feel like a failure. You are NOT crazy, a failure, a horrible parent, etc. You are young, your hormones are probably way out of wack, and none of these things are within your control. There is absolutely NO SHAME in getting some help with your feelings, and seeking someone who can help you cope. If let go, PND CAN be dangerous, as things can escalate beyond your ability to control your behavior. I'm not saying you are anywhere near anything remotely like that, but as a preventative measure (and hey, just because you're worth it, and so is Gabriella), you should get help for both of you. PND is a really common thing after a woman has a baby, and there are varying degrees of it, and it may feel a little different from mom to mom. Maybe you could talk to your parents about your feelings, and ask if you could speak with your OB or doctor about what's going on, because I do suspect that it's a bit more than just making a serious life adjustment...it's a real condition that requires real treatment, and it has nothing to do with your character, your love for your child, etc. It's just one of those things, seriously, and it's OKAY.
Like I said earlier, just keep chugging along. Things do get easier, and perhaps with a bit of extra help dealing with the hormonal changes, you can start to feel better about where things are standing currently.