Weightloss Slowing Already...is this normal?

Hi everyone, I have had a wonderful experience with the gastric bypass surgery I had almost six weeks ago, and I'm very, very happy with how it has turned out. Even the fact that I haven't lost weight at the pace I thought I would hasn't totally discouraged me...I am hoping the slower it is, the less extra skin and hair loss I will have and I keep telling myself I'm not on a schedule...I want to lose 100 more pounds to reach my goal weight of 140 by my 40th birthday which is next May...more than a year away. My question, however, is that I seem to be the slowest person ever at losing weight and I can't figure out why. I've only lost 40 pounds in eight weeks. (two weeks before surgery I lost about 18 and the other 32 has come off since March 21st. I know this sounds crazy and is not that slow compared to a normal diet, but when reading other profiles of people my age, height, and starting weight who seem to drop the weight faster, I must admit deep down I am getting a tiny bit discouraged and am wondering if I am doing something wrong. I get 60-70 grams of protein, 60 -80 ounces of water, all of my vitamins, and I am eating anywhere from 550 to 650 calories per day. I am 5'5" and currently weight 240.4 pounds. I've weighed anywhere from 239.0 to 240.8 for the past week, whereas I was losing .3 to .5 pounds per day before this...I did have a couple of ups and downs, but they evened out after a couple of days, but this seems ridiculous. I even stopped weighing for 5 days to stop myself from obsessing over the scales, but when I got on them yesterday and saw that even after days they went up, it ruined my day. Logically I know it will eventually work itself out, but I was wondering if anyone else went through this in the beginning? (I did start exercising at my Jazzercise classes this week so I know I've built a tiny bit of muscle, but I didn't think that would stall my wl completely.) Any words of advice would be greatly appreciated!!!

Misty listen to the experts . . . I am going to cut and paste this post for future use. Thanks for asking such a great question. I might not need the answer now but I am sure I will later on. Again thanks for the question and thank everyone for the great answers. I look forward to using this reference later on. Phenom