Is My Diet Healthy?

Common knowledge says you should not starve yourself to lose weight. By no means do I believe I'm starving myself but I've lost 11 lbs in 18 days. I know a bit about water weight and you lose a lot at the beginning and it starts to level off after a few weeks.

The thing I'm concerned about is the fact that I'm not THAT much heavier than my target. I couldn't imagine losing this much this quickly. I started at 220 and my goal is to get to 190. At my lightest as an adult I was 185 with 7% body fat so I knew it would be tough to get back to that (I actually never thought I would be able to). I certainly didn't think I would be a third of the way to my goal three weeks in. At this rate I'm going to be able to fit into my fiancee's wedding dress. Other measureables: 6'2" athletic build.

Do you think I'm not eating enough? I believe my diary is open to the public but if it's not a typical day in the life is between 1400-1800 calories (a few days I did not do a very good job of logging). I then go to the gym 4-5 days/week and do 20-40 minutes of cardio and some weight lifting on the days with lighter cardio. My net calories are around 1000 on gym days.

On the first couple days of the diet I was feeling hungry between meals but I attributed this to the fact that I used to eat quite often and in come cases, over-eating. I thought it was just my body adjusting to the new plan. The hunger pangs were never unbearable, but I knew they were there. I have never felt ill, light-headed, tired, etc. in the last three weeks.

I don't want to starve my body to the point that I lose muscle or I hurt myself. Is what I am doing healthy for my long-term success?