I found a couple websites yesterday that said some of what you said. They said that plateaus of 2 - 4 weeks are normal. I was glad to hear that. One site mentioned eating too little. Recommendations were also to change what kind of diet I'm on for a few days, like high protein, shakes, or increasing calories. I'm trying to push myself harder on the treadmill and more frequently. And I did some crunches today and a few pushups.
You mention 1000 calories being low. I put myself on that diet. I'm supposed to just eat less and healthy. I'm not great at the healthy, so to keep myself in check I watch calories. When I saw my gastric doctor in late July I told him I was eating between 1000 and 1200 calories and he only said to make sure not to eat more than 1000. He's in the top 10 percent in the country. But one site I went to recommended eating 500 calories less than you need to maintain. I'd be eating 2000 calories if I did that.