Hiya,
Unfortunately I've never been on Lighter Life (or any similar plan), but what I do know is that the weight loss expected per week/month is very different.
SW isn't a quick weight loss plan - they say a 1lb loss per week is average over the course of following the plan, so you're only just under that. You've only been doing it a few weeks too - I gained on my first week on EE - and I think your body will need a little time to readjust to this different way of eating.
Are you using your healthy extras and syns? They're quite important for weight loss on SW so don't miss them out! If you fancy, you can post a food diary and we can all be nosy and see how you're doing?
Hope that helps a bit, and good luck (and well done with your weight loss already).