Find a mentor - I've been through a similar situation years ago (happy to help if interested). As others have said, make sure to get a comp/title change in resp

Find a mentor - I've been through a similar situation years ago (happy to help if interested). As others have said, make sure to get a comp/title change in response to you taking on additional responsibility. What I think you'll find as you grow in your career, is that what you say no to (and your ability to focus) will become much more important than your ability to take on more and more tasks. We're all human and will have breaking points, so maintaining the ability to focus is crucial. Don't let your lack of degree or business training discourage you. A lot of leaders at start-ups today have similar backgrounds, and are learning on the fly. One area I found difficulty assessing was identify which stress was me growing into a role versus which stress was self-imposed. I worked with an executive coach to help learn the difference and make some small tweaks to my behavior. Hang in there, say no more often, and reach out to others who have gone through a similar transition for help.