So sorry to hear you lost your job, it's pretty traumatic, going from working every day, dead lines, things that important to suddenly, none of that's important and not your problem. Personally I've found it jarring the few times it's happened to me, and it's really hard.

So a few thoughts:

1. Were you the only one laid-off or was a portion of the org?

2. 3.3 million people in the US filed for first time unemployment last week, and it'll surely be similar this week.

A couple of weeks ago I got asked "what if we need to cut engineering staff?" And we ran the numbers. Of course the first thing I did was push back, we won't be able to hire them back, it's an amazing team of dedicated engineers, if the bad times are 4 weeks this will gut our skill set, at this level what managers are left, do we need any? Certainly don't need me. Thankfully we found a way through without cutting engineering staff.

It's pretty dreadful on the engineering management side, though not as devastating. I never want to let any of my team go, but I can't be a petulant child either. :(

How we pick people...sometimes it's seniority, or experience with the product/team/etc. Sometimes you just have to reduce to meet burn rates.

I don't want to recommend any 1 leadership book. But leadership comes in big L and small l versions. Technical leadership is important, and something I would expect out of any team member with 15 years experience. Much of the literature focuses on how to be a big L people leader, but if you want to stay technical ferret through all the books and find a book focused on how to be a technical leader/architect/etc.