Here's what might be the problem, plus what to do to prevent your cookies from spreading. They can be saved yet!
Tips for Using Cookie Sheets
Why chill cookie dough and other techniques to stop cookies from spreading - The Bake School
Cookies spreading? It might be your pan lining.
Biggest Baking Mistakes People Make With Cookies and How to Avoid Them
Cookie Troubleshooting Guide
How to Keep Cookies from Spreading - Bake or Break
9 Tips to Avoid Flat Chocolate Chip Cookies
Why chill cookie dough and other techniques to stop cookies from spreading - The Bake School
How to Bake THICK Cookies - Handle the Heat