I have 50 photos from Feb and unopened pkgs of pocket pages sitting on my desk for a week that have been met over and over with a blank stare. I'm doing an album a month for my project 365 and decided on pockets for Feb. Jan was a mini album and I buzzed right thru it. This month, however, I feel like I don't even know where to begin.
Where do you start for working with many photos at once. Plan your layouts first? Organize photos and work the pages as you go through them? Ugh... I don't know why I am at a loss for this right now. Needing some motivation, I guess. 
Poor Amanda ... feeling overwhelmed lol .... I don't like working with big numbers either .... I would split it up a bit into seperate piles depending on the subject and work with them that way. Once you have one group done then move on to another making new groups to fit your page. Not sure if it will work this way for your photos but it always worked for me when I had a quilt load of blocks to work with, all different and scrappy. Sometimes I would have to change a few blocks up but with each group done it made it a lot easier to see if something just was in the wrong place
I am in a similar situation going back and doing past years of photos in pocket pages. I decided to do it month to month, or event to event.
For my month to month books, I get all my photos together and plan how I want them grouped together. Then I choose pages and decide how many will go on each page. And then the building goes from there. That is the easiest way I have found to do something that is not my weekly books, which I have an actual planner for now.
That sounds tough! I would agree though, go through the photos first and see what you are working with, and I bet once you start going through the photos you will find a rhythm for those pages. Good lucK!
If it's a bunch of random photos, I usually just go by the weeks. So I sort the photos in separate folders by weeks and then work from there. Makes things less overwhelming. Or if things are more occasion based, I'll work based on those.
I have teenagers and am starting to scrapbook photos from prior to their births, I've just been thinking of my all time favorite photos and trying to feel inspired from there. You're right, it's as overwhelming as much it is fun!