I don't know if this will help, but I'll put it out anyway.
I see my transition in the metaphor of a script or screenplay, in that it can be (and usually is) loosely divided into three acts.
Act 1 -- wherein we introduce the major players and set up the relationships and needs/wants which will act as the 'motor' to the plot for the second and third acts. In the typical Hollywood movie, act 1 lasts for 5 to 15 minutes.
Act 2 -- the longest act. All the stuff that was introduced and set up is now allowed to work itself out. This usually means a series of setbacks and blocks that need to be overcome to reach the plots' stated goal. The end of Act 2 is usually the beginning of the final showdown. It lasts at least an hour, if not longer.
Act 3 -- Final showdown/resolution/denouement. The hero(ine) overcomes all obstacles to reach the goal -- sometimes with a twist to the plot -- and wraps up all the loose ends in the story. Usually the ending is some variation on 'and they lived happily ever after', or at least their lives establish some sort of new and different equilibrium.
My act 1 -- After reaching middle age without being able to shake this feeling that there's something not right, not whole, not integrated about me, I tangentially arrive at the realization that I'm well and truly transsexual, and with a desire to transition I can no longer ignore or put off. I seek out and meet with a therapist who specializes in GID and specifically transsexuals, and I (a little plot excitement here to keep the audiences attention,) manage to convince him that I'm likely transsexual. Act 1 ends when I get my 'scrip and begin HRT.
My act 2 -- This is the long act, and I've only just begun. The things I can see on the horizon are -- 2 months after starting HRT, seeing if I'm hooked on the stuff and MUST continue (confirmation of the GID/TS diagnosis.) As I continue to feminize, dealing with the yahoos and the curious -- most of the attention benign, some malignant. Probably several personal crises' with family/friends/employment over my transitioning. Making the decision/preparations for GRS -- probably around a year from starting HRT. I see act 2 ending in the OR as I try unsuccessfully to count backwards from 100, blacking out at 95...
My act 3 -- will probably be about a year or two long, as I accomplish final adjustments after having gotten the surgery. It may or may not involve post-surgery depression. I hope it has a happy ending, with me fully comfortable in my new gender role, and with a large circle of accepting acquaintances, friends, family and co-workers there as a support system. Of course, in Real Life, there can be bad things that happen after and-they-all-lived-happily-ever-after-the-end. I hope that those bad things will not be related to my being a transsexual, but will be the normal bad karma that affects us all from time to time. Well, I CAN hope...

To tie it into your post, Kimberly;
I hope what I've written can act as another viewpoint, to allow yourself to pull out of your musings and look at it with a bit of objectivity. If you don't like my script metaphor, try something else more to your liking. The point is, acknowledge your anxiety, but take a meta look at what's going on.
Now, what are you doing right now? Are you dwelling on the future? Are you dwelling on how you're not where you imagined you would be a year after accepting yourself and 6 months after beginning HRT? Throw the calendar out! The script is just an idealized plan, nothing more! BE HERE NOW! (Google that phrase.) You'll complete transition -- your feet are on the path, and every day you're taking steps towards the goal.
And remenber, surgery(ies) are not the end state, but mileposts. A year or two after GRS you might,
might, 'complete' transition, or it might take more years.
As part of my journey, I like to visualize what the future might bring -- what I might be like and be doing 5 years from now. What do I visualize? I'm spending a Sunday afternoon in Harajuku in Tokyo, watching the parade of strange costumes go by, and giggling at some of the more outlandish ones -- perhaps I'm wearing one that other people are staring at; I'm on a video shoot, I've just successfully dealt with a butthead male on the crew, and now we're back at work setting up and taking shots. At the end of the shoot, several members of the crew say they really enjoyed working with me; I'm shopping for dinner at the supermarket. I'm chatting with an acquaintance who is a store employee. We have a long-running conversation spaced over many short visits. When we part, we bookmark the conversation and resume it the next time we meet;
Etc, etc, etc...
But, that's in the future, I try to be here now.
Kimberly -- be here now...
Haz