QUIT. QUIT QUIT. Don't get used to abuse and enslavement!
You have been working there because you have a brain which an organization can utilize and make money. Therefore, it means outside that organization, you will still have your brain which you can hire out to the best bidder, which includes yourself.
You can start a consultancy, if your expertise is in service provision or you can selling products, if your expertise is in selling goods.
Please please don't submit yourself to door-mat status.
Most importantly quit honourably. Don't leave clients hanging. If giving notice will make the situation worse, resign gradually. Start mentally, hand over key functions to a colleague then one Friday hand in a 'well written' resignation letter. Don't cite your frustrations in the letter. Just thank them for the opportunity to open your eyes to higher heights.
Kikuyus says 'kiraro gitimiyagwo' meaning 'you don't shit on your bed' because 'kumagwo ni gucakagwo meaning 'you might go back to a place you've left'. I remember after quitting my first job, my boss 'hired' me via my newly registered company.
I din't go back as a slave but as a King.Company to Company.
In the meantime, I hope this
article will help.