You have alot on your plate guy. But, I have to commend you for all that you are doing. Is there a reason that you are not seeking the advise of a trusted dr.?
I agree with JS. Go ahead and talk to your doc about any of your health concerns and if everything checks out okay, maybe try going to see a mental health care professional. I have found talking to someone that understands this is a great way to confront and deal with it.
I should hope that among your resources as an RN is a community of doctors who include one or two who can consult with you on this.
My opinion is that the apnea -if indeed you have that- can be sort of scary in and of itself, especially if it comes with a dream about suffocation or some such (which may NOT be rememebred). So, if you have a predisposition to anxiety/panic, then I can scarcely imagine not breathing would come as a relaxing change of pace.
The herb? I dunno. But the talk of herbs will no doubt bring a flurry of responses and enthusiatic testimonials about a few of them. The problem with an herb or a med or any particular "thing" is that it gets us into the try this, try that syndrome. How about a consult with a trusted doc (there's always one or two) at work?
Let us know, please, how it all goes.