Have you never been involved in a long project that was initially unfruitful but ultimately rewarding when you stuck at it? It's not supposed to be enjoyable, you're nurturing your child to establish the foundation on which your life together is built and to help them prosper.

You're right, it's extremely mentally challenging in those first months before they start to communicate with you directly (as opposed to general communication of crying!). But it's part of the whole experience that bonds you together in a way I'd never have imagined was possible.