Hi, and welcome!
"They" say that 3 x 10 minutes walk each day is every bit as effective as a single 30-minute walk, so maybe you could fit in ten minutes in your lunch hour, say, and another ten minutes after work? Two of my friends have recently committed themselves to a ten-minute walk after dinner, too, although I'm not sure how long they'll keep that up on cold, wet winter evenings! All the same, if you can fit 30 minutes' walking into your day one way and another, you might well feel fitter!
Also, I don't know how much, if at all, you have modified your diet, but you might consider either cutting back on carbohydrates, or at least switching to low-GI ones. Bearing in mind that we are all different, and some people can eat far more carbs than others without upsetting their blood glucose.