You feel like this because you're body is trying to make sense of all these hormones floating around and get them regulated again! I crashed like that at the hospital, i started having panic attacks. It was terrible to feel that way and know that it wasn't based on reality, just hormones. I had an ideal birth experience and it worked out better then I could've planned, and better then I was afraid of. I would feel so guilty reading stories about women who gave birth to babies that had severe deformations or complications. What right did I have to feel so bad when I had a beautiful healthy child, who was growing and breastfeeding fine (my first wouldn't and had a weight loss crisis at 5 weeks). I got so irritable with my family who'd traveled long ways to help me out. I just wanted to disappear!
However, that lasted about 2.5 weeks and even before it ended it was getting better. I was on 2 low doses of Xanax daily and in a few days was able to drop the morning dose. It took the rest of the time to drop the evening one, but it did go away completely! And the Xanax did not cause the baby to be too drowsy or inhibit my milk supply.
I also had the same feelings of wanting a tubal initially and then feeling bad about not having another child. Unfortunately I can't have another child, its very risky as my daughter's and my blood crossed at some point and now I have rare antibodies in my blood that would make things very complicated with the risk of miscarriage and deformity. We'd planned to stop at two, so initially it wasn't a big deal, but I did have to deal with and grieve the loss of having another. And my husband the loss of not having a boy. I was surprised that I felt sad about it, since it was part of the plan.
Hang in there. It gets better. One thing I found that helped me was talking to friends and family. See if one of your friends could drop by daily to check in on you, boost your spirits. Try to get out of the house, go to the mall or somewhere you can relax and see people walking around. Get some fresh air, maybe bundle up and jog around your house once or twice, it will boost your energy and mood. Focus on doing one chore a day around the house, that helped me a lot, feeling useful! See if your community has a PPD support group. I didn't go to one because it was a very long drive from where I lived, but I think it would've helped! Connect with your friends via social networking sites, that helped me a lot as I was new to the area (4weeks before baby) and didn't have people to check in on me and family lived 6+ hours away.
You'll be in my prayers, PPD is really tough and I don't wish it on anyone, but you can get through it! There is light at the end of the tunnel and you'll start feeling like your old self soon!