How long do you jog? If you can only run for about 6-7 minutes straight and only do this 2 or 3 times then maybe start trying to slow your pace so you can jog for 30 minutes straight. I am now running 5 miles a day (or slightly more if i get a wild kick) and believe me it took me a while to get up to that even though I am in good shape. My weight fluctuates often depending on if I am trying to put some muscle on or if I am trying to lean up. The extra weight doesnt make that much of a difference, you just have to get your heart and lungs used to it, take your time.