I am one of the three people in the western world not on fb, avoided it owing to work, so will just wait kri5ty. I will definitely get some lactulose- is it something you can get over the counter, or is it prescription?
And now...please, please don't feel guilty for not 'achieving' a normal birth, whatever one of those is. It sounds like you had a rough time of it, so the last thing you need is to add to your own troubles.
You're about 3-4 days post natal, which is classic baby blues time. Feeling like shite and sobbing is normal at this point, even if you've had the birth of your dreams. It will pass, but like with depression it just doesn't feel like it when you're in it.
Also, if you've had a tough birth, you'll be physically exhausted, bruised and sleep deprived, and the drugs that you're on will also be affecting how you feel. You wouldn't expect to be singing and dancing if you'd been in a car crash, and so don't feel like you should now- there's no normal to measure up to. Your body (and mind) will probably be in a degree of shock, and so it's concentrating on itself, if that makes sense- in a way it won't be able to 'manage' that lovey feeling, but it will come.
Finally, YOU ARE NOT A FAILURE. Far from it, you've achieved something wonderful, and you've made a little family for the three of you. You are due massive congratulations.
Keep posting if you can.