Is my loss healthy?

I have been dieting and upping my exercise lately. I currently weigh about 230 pounds and am 5'3". I was up at 260 pounds within the last year. I did weight watchers and had some success but I would always forget the slider thing to calculate points and trying to do the core program where there were foods I couldn't have was impossible for me. So I did a little research and found that to maintain my weight I should eat 2300 calories. I've been eating between 1500 calories and 1800 calories and feel fine with it. I don't feel deprived in any way or hungry. I've also started working out 3 to 5 times a week and feel fine with that too. I'm not sore most of the time and the days I do feel sore I take a day off and soak in a tub of epsom salt. Sometimes I even take two days off. I've been doing this for about three weeks and have been losing 3 to 5 pounds a week. Is this healthy? I'm thrilled with the results but am worried it's too drastic and could cause health problems.