Sorry. I’m not a Trimble employee. I’m just a volunteer trying to help you. If you were using the 30-day trial of SketchUp Pro as Colin indicated, your saved SketchUp file would be on your computer. Have you looked on your computer?
You don’t need to have SketchUp Pro to access a model you made with it. You need to search your hard drive for the file. What name did you give it? Search for that name. When you find the .skp file you can upload it to the web version. Then if you want to continue using SketchUp for work you can purchase a commercial license.
Your SketchUp trial works until April 10th 2022. It looks though like you ran SketchUp 2021 for the trial. If you did, open SketchUp 2021 on your PC and look at the File menu, for what documents are listed near the bottom. See if any of those are your missing files.