It's a job, so you'll face the day-to-day stress of being a working stiff: long hours, unreasonable deadlines, and irascible bosses/co-workers/clients. And if you're trying to break into this highly competitive field, you'll get used to the stress of rejection (unreasonable, in your humble opinion). And if you are a freelancer, you'll see stress in the form of hustling day and night for your next job.
Face it: Creative work equals stress. But hey, if you love what you're doing, stress is just one niggling slice of a big, beautiful pie of creativity.