There's a known issue with HP-buffing gear that causes the effects to stack whenever you enter a new locaiton. Effectively, by the end of the game you'll be invincible. It's weird, but it seems to be happening at the system level, so the only thing I could do about it was take out all of the gear that gives HP+. But that doesn't really help if you come into the game with a bunch of it, obviously.

So if you want to play the story as intended, roll a new toon, or dump your HP+ gear into the stash when you get to Shannon's.

I'm not going to turn off the option to import, though, becuase I'm assuming that if you're doing that, you probably intend on ripping through the story as unimpeded as you can. Just be aware that if you keep that gear equipped, it probably won't be much of a challenge!