Awesome. Thanks for the clarification 
The docs are great for learning how to quickly and easily add Forms functionalities to purely static sites. React-based Static-Site-Generators like Gatsby get a little more complicated. There are new guides in the works to help alleviate that! In the meantime, this comment should be able to explain to you some of the under-the-hood as to why your current form isn’t working quite right.
The tl;dr for you is that you just need to add an additional input to your form HTML in your jsx. If you can go ahead and add
<input type='hidden' name='form-name' value='contactNuh' />
to your form HTML, I believe the form should work.
–
Jon