As if it weren't bad enough is a phrase that will be followed by two events, one 'bad' (as in bad enough) and one even more so.
As if it weren't bad enough that I fell off the horse (first bad event), it then kicked me in the leg. (second bad event)
As means as though or like. When you use as if, you can use the subjunctive, though it isn't strictly necessary, especially if there isn't anything unreal about the situation:
- She looked through me as if I weren't even there (he really is there).
- He remembered that day as if it were yesterday (it wasn't yesterday).
- He laughed as if it was some kind of a joke.
As if it weren’t bad enough that I wrote my first book during our first year of marriage, I wrote this book during our first year of parenthood.
The first year of marriage is a time to get to know your spouse, set up a home, etc. It's busy enough that writing a book is difficult. But the first year of parenthood is even busier, and an even worse time to write a book. Hence the as if it weren't bad enough. In doing so, s/he robbed him/herself and spouse of quality time together.