I am not a fan of running - my knees, ankles, shins, and back kills after an actual run. So, I walk. I started at 5 minutes, downloaded some weight loss podcasts onto my iPod, and just kept walking. I got all the way up to 60 minutes and on higher inclines (the 2nd cross country setting I think).
I recommend not running, but walking. Adjust the incline, try a few different settings. My average speed was 3.0-3.4 mph. The point of weight loss is to keep up your heart rate up for X amount of time. And, to cut the boredom, listen to podcasts, audiobooks, whatever. When I listened to a podcast, I was aware of the time frame, so I knew that it would hold my interest for 35-60 minutes. When I worked out at home, I have a playlist of songs to help me time my workouts.
So, is it enough? It sounds like even 5 minutes of running is tiring. I would try walking and see what the different settings can do for you. For me, it really toned my thighs, hips, and butt. It also helped my balance and posture - just by walking.
Hope this helps