Please note I'm not talking about the difficulty of finding players but when you actually summon them in or invade. I'm not enjoying PvP at all because I feel like every fight I have is just a lag fest, and I constantly get hit with backstabs and attacks when I am clearly blocking with them facing me.  
 
So is it just my shitty internet or w/e that is the cause or is it the game? It's really disappointing and annoying having to fight the lag and all of the stupid stuff in this game (fog ring, slow spell, lightning weapons, ect.) 

I just summoned a dude for the first time and it was lagging like crazy so don't think it's just you.
 
On the topic of PvP, got invaded for the first time not long after I summoned that guy and wtf...do not like.

I usually love PvP, I just can't handle dying 90% of the time because of some bullshit rather than actual skill. Getting backstabbed for 80% of my life when the guy is no where near behind me... fun. 

As someone who loves invading other peoples games I can see where you are coming from. The combat when fighting another actual dude needs to be pretty lag free to make best use of the combat mechanics and the 10 or so times I have invaded/been invaded it's been pretty choppy. That being said it's something you get used to. You learn the tricks to not get back stabbed and in some cases get some lucky shots in you probably shouldn't. Just remember when you get invaded the only way for early invading players to heal is using humanity items so as long as you're in for the long hall, and maybe have a weapon with bleeding, you can tear up unprepared invaders.

What exactly "tricks" are there to not get backstabbed?  
 
And I just feel like I'm already fighting an uphill battle against things such as the fog ring without having to also figure out dealing with the lag. I also feel like these guys just running around with these massive +5 lightning weapons or whatever benefit a lot more from the lag. 

Yup got worked hard from one invader. It was almost like he was using a lag switch. He would literally disappear, only to reappear at the worst opportune time and hit me a few more times than he should have. Also I was getting hit when I was very clearly blocking.

Another time when I summoned in a dude, the world itself was lagging. We would kill some enemies, but then they would just stand there or continue to walk around, neither alive or dead. The wouldn't attack us, but it took a good minute for the creatures to finally fall to the ground.

I really hope they patch the hell out of the online stuff. The ideas behind it are so damn cool, I want to play with it more!

Try having it lag so badly this dude was casting Tranquil Walk of Peace with a pyromancy flame. And I can't kill him at all. No matter how many slashes I've land and backstabs I did. The game just didn't register anything for his last 2 points of health. But I did get lucky once and finally pulled off the final 2 damage on him, but still... Either he was hacking or the game lagged balls.

Also, I've pretty sure the game is structured such that the invaded individual becomes the host and has host advantage.

Yeah, however Namco Bandai handled the servers, it makes it lag pretty bad most of the time.

So I'm not getting much lag today... but I've had 2 guys now who literally plug pulled or something so that I wouldn't kill them.