Tiny text tool

What is the resolution in PPI of your document, from Image > Image Size?

Actually I think it's the physical dimensions that dictate what the font size looks like, not resolution. So if a file is 72ppi, and 100 inches, the font will look tiny. If you take up the resolution without resizing the document, the physical size will go down making the font look larger.

Uncheck the Resample option and change then resolution. Try 100 and see how that works. 300 will make your font even bigger.