Losing with limited exercise??

I did the same as you when I started, I went crazy on the exercise and triggered an existing back problem!

I had to scale down my exercising dramatically, I found that I lost more weight when I just tracked my cals.

I now do a lot of low impact exercises such as cycling for short periods of time and then a light walk on the treadmill, I've also started going to the pool and walking in the water to take the pressure off my discs.

I also do some pilates,

Hope you find an exercise that you're comfortable with soon