Advice on “Intellectual Property”

I am a CAD technician at my current job, in which one day a group of people in my company decided it would be "AWESOME" to provide a way for anyone in the field to look at current shipping/order information as multiple schedulers put it up on the board(spreadsheet) via google sheets. I was doing my work one day and this group came in and "hinted" that they needed someone to do this. Ends up that was me(as they intended) and I was Volun-Told/tasked with this project (I was previously a developer in which they knew). I had only been there 4-5 months and couldn't really say "No" due to the fact that I was the New Guy. This started off as a simple spreadsheet and ended up being a bit more. It is built in G-Sheets and like I said has grown to a much bigger project in which it saves many people a lot of time. I built this outside of working hours simply b/c there is no time for me to do it at work(they allotted no time). I have yet to be compensated for this task which has taken many hours to make a spreadsheet function as a piece of software so-to-speak.

I am a bit overwhelmed at this point and want to know if I take it down and quit the project(again has nothing to do with my job) can they somehow confront me with a legality of some sort? My understanding is that since its not company software(g-sheets), it was done on my time, and it does not apply to my job, they cant really do anything. I would also not like them to use my formulas and code if I take it down. Do i have this right? What can they do? Could I get fired? Any professional opinion is appreciated. Thanks