It's tough being a parent, extra-tough being a single parent, and I think extra-extra tough being the parent of a kid who the opposite gender.
I have an 11-year-old and one thing I've found really helpful throughout is "ages and stages" sorts of books or online resources, that tell you what to expect for various developmental stages.
I find it reassuring because so much of what we take personally is really just very typical for the age.
That's not to say that we just sit back and say "go ahead, be obnoxious, that's the developmental stage so I don't care" -- we can still offer correction and not accept unacceptable behavior.
But it can help take some of the emotion out of the whole thing. And the emotional stuff is how things get ratcheted up pretty quickly.
Anyway, I just got a book called "your 10-to-14 year old," let me look at what it has to say about 13-year-olds.