My two cents worth, for what it's worth. There are many post-apocolyptic series available. Many are pure trash, but some are worth reading. The Ashes Series by William J. Johnstone has been around for quite a while. Probably over 10 years. Pretty good reading until the 30th or so book, then gets so repetative and formulaic that youjust want to kill off everyone in the books. Even Johnstone admitted toward the end that he'd tired of writing them.
John Ringo is one of the newest hottest military sf writers around today. Writes very well and is able to pull together a myriad of characters and subplots to maintain a great storyline. His Polseen books concern an alien race invading earth, but is pulled off well. About 10 of them out now.
Another, older series you might like is The Survivalist. A series by Jerry Ahern. Like the Ashes series, it is a true TEOTWAWKI storyline--world devestation by war and plagues. A side note for us gun nuts, Ahern's central character used Deutonics 45's and Ahern gave up writing and bought the company. I believe it is still in operation today.
All these books can probably be found in used book stores and in some cases quite cheaply. Especially the older ones. Or check E-bay. I have seen whole series sold for basically just shipping costs.
I would offer my to you, but unfortunately they were lost in the Great Nashville Flood of '10. Seriously, I lost about three thousand books and paperbacks dating back to the early seventies. Yes I know, that's stupid; but I've never been able to get rid of a book if I liked it.
Anyway, there are losts of books out there on this topic. Most are purely for entertainment purposes, but can have some redeeming value by giving you a bit of knowledge about survival skills and tactics. The trick is discerning the truth amongst the fiction.