Heh - I love my job, but I don't know, bro... There's lots of times I'm standing on the dock at 7am, it's 40* outside, and raining sideways...
When we did the big barge/boat/vrane salvage job, it was wickedly cold, the water a briny, zero-vis brown, with a pretty massive diesel slick on top.
On those days, I stand on the dock and think back about what it was like to arrive daily in a warm, bright, dry office, sipping a cup of coffee, saying, "Just point me to what you think the problem is..." Life was simpler then, with a sure paycheck, clocking out on time, and benefits and 401k's. I often spent time online on forums and email between waiting for programs to load.
...Then the sun breaks, Spring arrives, and the local kids stand atop the dock saying, "Wow... What a cool job." And the checks arrive... Sometimes payday is every day.
When I question where I am and what I'm doing, all I have to do is stop what I'm doing and look around and see... My office. The water, the dock, the boats, the birds, the sun... Oh yeah, this is why I do this.
Yeah, I wouldn't change a thing. This is the hardest job I've ever loved.
If you're considering it, do what I did - do it on the weekends as a side thing and see what happens.