Tbh, there is no way you can plan that afr ahead all the issues having a child can throw at you.
I didn't plan to have PND, I didn't plan that dc2 had AS, I didn't plan I would develop ME.
Do you cope?
Yes in most cases you do.
Some times, you need some support to do so though or rather having the support means that things aren't as hard on your dcs (I'm thinking my illnesses there)
As for how you cope, again everyone does it in their own way. I. READ. A. LOT. Every book under the sun about parenting etc... until I felt I had a better idea of what I was doing.
Other people feel their way through, go om MN, speak to their friends, etc etc.
And then you just muddled through because you have no other choices than to do so!
Some people will tell you that it's their love for their child that has carried them through it all.
Finally, it is worth remembering that happiness in people dips when they have children and inl;y goes back up when they live home...
Which tells me that, yes having a child can be a great pleasure but it's also a big responsibility, a lot of work and endless worries (some small, some big)