One thing to ask yourself is whether you'd really enjoy teaching. Some students at lower levels can be really impatient and inconsiderate. And if you're good at math, it's generally a pretty big shock to see the level of the students in some of the lower level classes. And even some higher level ones, too. It can be a challenge to get though to them. For example, you might run into an algebra student who says 7+3*4 = 10*4 = 40 because they don't know the order of operations. You have to realize that they're not stupid for making that mistake because the order of operations is purely a matter of convention, so you could be a genius and if you don't know the convention, you miight do the same thing. It does show a pretty profound lack of familiarity with the material they are supposed to have learned, though. Anyway, these things are so ingrained in you, if you've done a lot of math, so what ends up happening is that you have to almost relearn what it's like to know next to nothing about math, so that you can understand how to communicate with these students. I don't mind that so much, but what I do mind is when students start playing the blame game and just get really impatient and judgmental with you about it, if you don't instantly read their minds and know exactly what to tell them. I know I wasn't a very effective teacher when I started out, so I was failed by the system because they just kind of threw me to the lions and watched to see if I could defend myself. So, the students may have had some right to complain, but it wasn't all my fault, either. You can beat the system if you have more of a natural talent for teaching or if you prepare by having quite a bit of tutoring experience with low level students before you start teaching. Another thing is that people are judgmental about very superficial things. A psychology prof did an experiment where he worked on his tone of voice or something and it was a night and day difference in terms of how he was perceived. So, some kind of enthusiasm and practice in front of mirror/videotape beforehand might help. Perhaps, if I had done these things before I had to teach, I would still have some patience to keep trying, but the experience I had was so painful, I can't stand the thought of devoting my career to it. I didn't have any idea teaching was that hard before I tried it.
You could try to become an engineer professor, too. Engineering can be very close to math and physics if you choose the right field, so I would recommend looking into it, if you are worried about getting a good job afterwards.
Engineering isn't just for money. It is also good for minimizing the amount of painful job-search BS you have to suffer through in order to get a job, and it's also about getting a job that's more interesting than one that you might have randomly had to get to use as a back-up plan when you fail to get an academic job.