You can use the phrase "I'm not ___ing" to talk about a situation that continues for some time. In the example above, the speaker is exercising every week, but she hasn't lost weight. So she says that she's "not seeing" results.
The speaker could also say, "I haven't seen any results" but that sounds a little like she's already decided to stop exercising. "I'm not seeing any results" sounds more like she's searching for a better way to exercise.