You are right on schedule for shaking in your boots. I was convinced about a month ago that I was CRAZY for committing to a tri. I got through the panic by just doing a mock tri with Felissa one day. We went to Sandy Hook (I was on vacation down NJ with my sisters in August.) and we did each of the legs. We took plenty of time in the transitions. We did it at the hottest part of the day (not so smart). It kicked our butts, but we knew that we would get through it.
So go on out and run at least part of the HM course at a slow pace. You'll feel better. And then you'll know what's coming and can do all kinds of positive visualization things between now and then (see yourself running victorious over the finish line) and you'll be ready.
WELCOME to the............. 13.1 MILES...CAUSE I'M ONLY HALF CRAZY TEAM.
You will LOVE THIS TEAM! It's amazingly positive and supportive. The members here are always willing to lend a hand, an ear, or a shoulder. They have done it for me and they will do the same for you!! We are here to support and encourage you on your journey to success. All the best to you on reaching your goals.
I saw your comment on another blog that you were using Hal Higdon's novice training plan for an October half marathon. You might want to look at Jeff Galloway's plan. I'm using it for my 4th half that I will run on Saturday and really like it. It's a run/walk plan. Much quicker recovery from long runs and my times are actually better!