Stress
It's a job, so you'll face the day-to-day stress of being a working stiff: long hours, occasionally unreasonable deadlines, and maybe even some irascible bosses, co-workers, or clients. Also, if you're trying to break into this highly competitive field, you'll need to get used to the stress that follows rejection. And if you're a freelancer, you'll see stress in the form of hustling day and night for your next job.
Creative work almost always equals stress. It's a harsh truth. But hey, if you love what you're doing, stress is just one tiny slice of the big, beautiful pie of creativity.