Have you setup you business model to allow for you getting the flu?
Success is relative. A lot of people considered my choices to not take certain opportunities as “failures” but these choices grew my career into what some 20 year olds think of as “success”.
I almost quit my current job early but stuck with it based on your advice. After a year I got to switch teams away from a toxic boss, to a team with great coworkers and significantly higher pay. I’ll count that as a win.