There are four different weight charts used to determine healthy weight vs. obese / unhealthy weight. On all four, you are obese. If you happened to lose exactly 40 pounds, you would still be obese on 3 of the 4 charts. My wife is 5'2. She has gained a lot of weight so that she currently weighs 130 pounds. I think she looks great, but her doctor is very worried about her health, as she is at a very unhealthy weight for her height. When I met her, she was 110 pounds, which is her ideal weight according to 3 out of 4 of the charts.
You should aim for 110 pounds. I don't think you will ever get there. Still, you have to have a goal or you will never reach it.