the average WLS patient seems to lose somewhere in the 15-25 lb range the first MONTH, so at 6 weeks out, you're totally normal. Of course, you will always find outliers to that 15-25 lb range, but they're outliers. Unfortunately, I think a lot of people's expectations are shaped by shows like "My 600 lb Life", but you have to remember that those people start out with MUCH higher BMI's than the average WLS patient.
I lost 16 lbs the first month, and 28 lbs at the two-month mark. I only record monthly weights in my spreadsheet so I don't know where exactly I was at six weeks out, but I was probably about 23-24 lbs down at that point. And I ended up losing all of my excess weight, over 200 lbs. So you've got nothing to worry about. In the end, it's your level of commitment to the program that's going to make the biggest difference.