You helped build something to a point that a job position was created for the CTO, and if you are passionate about what you're working on and eager to learn, it

You helped build something to a point that a job position was created for the CTO, and if you are passionate about what you're working on and eager to learn, it's unfortunate that he took the approach of telling you that you "are not good enough" rather than mentoring you and helping you grow as a developer. I'm sorry for your situation, it's rough. That said, is this someone who you want to be working closely with? It could be something in your work relationship that is hard to get past. As others have said, understand what you are entitled to in terms of contracts and equity, and try having an open conversation with the CEO if you haven't already. Handle it professionally, and keep in mind that if you are desperately needed now (as you said) that you have some bargaining leverage. :)