Butterball - the fact of the matter - Exercise is GOOD for you!
My experience with the whole exercise/low carbing is this:
When I only low carb, I seem to drop actual weight faster than with exercise. However, when exercising, you will still lose weight (at a slower rate - especially in the beginning), but you will be losing A LOT more inches. I can give you an example.

I was low carbing solidly for like 5 months late last year. I started exercising towards the last couple of months, and my weight loss slowed down, but I maintained, and made sure to take my measurements. It was frustrating at first that the scale wasn't really going down...but learn this from me now...the scale is EVIL, and you should be monitoring your measurements more closely than the scale. I started thinking about stopping the exercise program, but then I plugged in my stats into mybodycomp.com . They show you how much lean muscle mass you have, and how much of your weight is fat. I was losing fat and gaining muscle. I think there was one week where I had physically only lost 1 pound, but when I plugged in the numbers, I had actually lost 6 lbs. of fat and gained 5 lbs. of muscle.

It's also healthier to lose the weight at a steady pace...I mean, we've all been there and been SUPER excited about losing 7 lbs. a week...but that's just not really healthy (and it has a tendancy to come back easier if it comes off fast). Exercise will help you control the pace so it's steady and healthy.

Like everyone says, talk with your doctor about an exercise program that would best suit you...but my recommendation...do it! You'll still continue to lose weight, and you'll be so much healthier in the long run.