I really didn't mean to scare you!
I didn't want to get across the idea that it's a nightmare (it doesn't need to be at all). But I am trying to get across the idea that it's all-consuming, in a way which is hard to appreciate before you're there.
WRT routine or baby-led, I think it depends on what you are like, and - importantly - what your baby's like. For me, baby-led was the only way.
I really didn't find the first few weeks hard, in the way that my antenatal friends all did, and I'm convinced I know why. My partner is self-employed, and we chose to be skint and have him home, and it made all the difference.
We went completely with the flow. If DS wanted to feed for hours, I let him. He slept when he wanted to and woke and fed when he wanted to.
Instead of imposing a routine, we introduced the idea of night and day to DS like this - in the daytime if he slept we put him down in a sort of carryable moses basket (it came with our pram) and let life carry on around him - we didn't lower voices or turn the TV or music down if they were on. If we were out we would stay out with him happily sleeping. After 7, if he fell asleep we put him down in his cot in our bedroom, but let him get up again when he wanted to. After a while (I forget how long) he developed his own routine and slept at night.
What made this relatively stress free was having DP at home. That's not to say it wasn't exhausting or all-consuming, because it was. A baby needs you constantly, especially at first. If you are on your own, suddenly even the simplest things like going to the toilet or having a shower become a matter of logistics (what do you do with the baby?) let alone more ambitious things like cooking dinner. (Reading a paper? Forget it!) It was such a luxury having DP at home, as I know it isn't the norm, but I really feel it should be. Our culture doesn't allow for this. Paternity leave should be much longer, not for the dads necessarily, but mainly for the mums!
Plenty of DPs go back to work after the standard 2 weeks, and people do manage of course.
For me, trying to impose a routine on top of being on call for DS 24 hours would have been incredibly stressful. Going with the flow gave me a chance to enjoy being a new mum.