URL Link to WP page w/params. What is happening?

I’ll lay this out as briefly as I can. We are talking about three WP pages here.

Page 1 contains a form where a user enters info and presses a button. The data gets passed to another WP page, page 2. Page 1 references page2 by name, without any .php extenstion.

Page 2, as it runs, receiving the data from page 1, runs a SQL query, with results relating to the data that was passed in from page 1.

Each row that it pulls is a 7-10 word phrase that comes with a link, with its unique ID.

The user then clicks on the link, and is transported to page 3. The issue is that it is looking for a page outside of WP. I am getting a page not found error each time.

The irony is that all of this worked this morning, and I am pulling my hair out trying to recreate this. How to I get them to talk to each other again.

The other piece of the puzzle, that may make a difference, is that I have changed the relationships of the forms, meaning parent-child, and think that this may have something to do with this.

If anyone can please offer some info, it would be greatly appreciated.

Thanks in advance