An Update, 6 months In

I've been a driver for right at a year. In that time, I've actually lost 45 lbs. The first month, with a trainer, I lost about 10 lbs. simply from the stress, the next month, my 1st month solo, I lost another 10 lbs from the stress. Stress levels started going down after that, but I was technically obese and knew I needed to lose weight, so I let that 'beginning' be a start and have continued to lose weight. Although it is not easy and in the last couple of months I haven't managed to lose any measurable amount, I also haven't gained any, so I take that as a small victory.
Anyway, it seems most gain some weight being a driver, but not all. It is alot to adjust to and learn and in the beginning, it is pretty stressful. I wouldn't be too concerned myself from what you said. Just my opinion.