Get your resume together - start approaching other companies in your area looking for developers, or start taking on freelance clients and spend your free time

Get your resume together - start approaching other companies in your area looking for developers, or start taking on freelance clients and spend your free time building up a small client base that you can comfortably live off. Once you know you have something that you can jump off to, give in your notice. Something similar happened to me as a sole developer (I wrote about it here: https://medium.com/this-happened-to-me/86b9d27f9962 https://medium.com/this-happened-to-me/86b9d27f9962)