A modern-day blacksmithing career is more stressful than playing a blacksmith in World of Warcraft, but less stressful than taking up this job during the Middle Ages. Fortunately, you don't have to worry about the latter.
Modern blacksmiths face a lot of the stresses that many self-employed artisans face: Will people like my stuff? Will I land a big commission this quarter? How will I walk home after accidentally dropping my pants in the forge, and what was I doing lifting them precariously above the fire with my tongs in the first place?
Okay, so maybe it's not exactly the same, but for the most part, your stress level is going to have an inverse relationship with your success.
If you nail down the clients, you'll be doing something you love for a living and you'll be your own boss. Fail to get the clients and you still get all that same stuff...but without the food, water, and shelter that comes along with it.