Reddit reviews Absolute FreeBSD, 3rd Edition: The Complete Guide to FreeBSD

I can't recommend this book enough. I started off much like you had, and learned everything I know from this book that is incredible. https://www.amazon.com/Absolute-FreeBSD-3rd-Complete-Guide/dp/1593278926

Absolute FreeBSD

That link points to an old edition .. here's the link to the latest (3rd) edition: https://www.amazon.com/Absolute-FreeBSD-3rd-Complete-Guide/dp/1593278926/ref=mp_s_a_1_1?keywords=absolute+freebsd&qid=1573610579&sr=8-1

First, read our Wiki. It is very thorough and answers a lot of these common questions such as

day to day? The Practice of System and Network Administration
And the topical reference books listed below.

Books to help in shaping a sysadmin? The above &:
The Phoenix Project
Time Management for System Administrators


Topical Books I see mentioned often and have been very helpful to me:
Powershell in a month of lunches
Learn Python the hard way
Unix and Linux System Administration Handbook
Windows Server 2016: Inside Out

Group Policy
AbsoluteBSD
FreeBSD mastery:ZFS
CCNA
RHCSA/RHCE
Pro Puppet
SSH Mastery

On my docket:
FreeBSD Mastery: Advanced ZFS

Michael W. Lucas and Thomas Limoncelli are very good sysadmin writers, you can't go wrong with a topic they have chosen to write about.

Most of the *nix stuff assumes a baseline knowledge of how to use a unix-based system. I learned as I went but did pick up an old copy of Unix Visual Quickstart Guide not too long ago at a used books sale, which seems like a good starting place for someone overwhelmed with sitting at a terminal and being productive.
I notice I don't have any Virtualization books, perhaps someone else can fill in good books. Most of my knowledge regarding virtualization and network storage has been a mix of official docs, video training, and poking at it. Seems innate but it isn't.