I think the weekly and monthly review is essential in GTD. It helps to prune the tree and keep it manageable. Otherwise it's just one big blob of tasks that just stares at you and laughs. You'll just keep adding to it and not prune it every once in a while.
I like to go into Review mode and then click each task/project as "Reviewed" when I get a chance to go through it all.
It appears you've gotten the collecting part down. The collecting part allows you to capture anything that interests you that you want to either dabble in, become involved in, or have a look-see....
Now you have to do the sorting part. The weekly review is essential here. Once a week, I use OmniFocus' review function to help me keep my tasks down to somewhat manageable levels.
For example, I'd like to look into getting a dive instructor's license or professional race care driver. But it's not necessarily something I place as urgent. So I'll put it in my Someday/Maybe folder.
During review time, I'll look at my Someday/Maybe folder and see if I am still interested in it. I'd delete it if my interest has waned over time.
Be ruthless with your task list. Look for tasks that can be deleted (nothing important really happens if I do it or not) or delegated (let someone else handle it).
Sometimes when I review something in the Someday/Maybe list, I'll elevate it and put it as my Big Rock of the Week or Big Rock of the Month. The someday/maybe list holds all the projects that I've been meaning to do and may get around to it. I'll review it and then determine one of several actions:
1. I'll just delegate and hire a contractor or specialist to do it for me (especially if it is not a task that I'm familiar with such as welding, major house repairs, or taxes).
2. I'll drop it (it's nice to have a swimming pool in the backyard but I don't think it's necessary quite yet).
3. Move it out of Someday/Maybe and into the Projects folder. Now it's on my plate of things to do.
If you are being overwhelmed by your task list, I'd suggest looking to see what is really important to you and then delete any tasks that just take up time and doesn't necessarily advance you to your personal goals.
Yes, that means you need to make goals. Kinda like a new year's promise.
Maybe you can look for books and blogs about simplifying your life?
I just started reading this other web site about simplifying my GTD setup
This fella's variation on GTD has really helped me with my GTD setup. Together with OmniFocus, I'm able to keep track of my interests that I never got around to (Someday/Maybe) and actually start tackling them one at a time. I've been reading up on blogs about simplifying your life to help keep my stress and blood pressure down.
Of course, there are some things that can't be avoided easily (the boss) but at least a big portion of my life has become more manageable.