Don’t think about a career as something you do for money. Try and think of a career as something you get paid to do. It’s a subtle difference, but on one hand, it’s easy to grow tired of doing something you’re not interested in and don’t have a pull towards. On the other, there may be some things in your life you would do even if someone isn’t paying you to do it. Try and find a way to make the latter overlap with your day job and it won’t matter what happens in these fields. A strong interest in something cultivates mastery and expertise and that will be worth something to someone, if no one else, at least yourself.