So it could be a new infection, or it could be a wacky test result. The only way to know is to test again. If you haven't had any symptoms, I wouldn't overly worry about it, as the hsv2 IgG has a decent rate of false positives, though yours is just an equivocal, which really doesn't mean much.
Should you tell your new partner? Well, do you want this to be a relationship? I don't think there's a lot of risk here, but say this is a new infection, and you find out 8 weeks from now that it is. You've had sex with this new guy for a number of weeks, knowing it was a possibility, but didn't tell him. He might not care about the herpes part, but that you took the choice away from him. That's a trust thing, which is important to relationships.
On the flip side, we are all responsible for our own sexual health. Even though you are beating yourself up for not using condoms, you are still blaming the guy who may not have been honest with you - do you want the new guy to feel that way about you?
So my vote is honesty. I don't like the word "disclosure" - that sounds so shameful. Make it part of the STD discussion you should be having - the awesome new guy could have something you need to know about, too, right? It's a discussion you enter on equal ground.
And stop beating yourself up. It's not productive or kind. Most of us have been there, and the best you can do now is just learn from it.
If it is herpes, I swear to you it's not nearly as bad as you think it is, but we can cross that bridge if we need to.