Hi GIGoddess, welcome to Social Slimmers
Congratulations on your losses so far, that's fantastic!!!
Personally, I've no idea when it comes to no gluten, no dairy, or low GI.
A couple of things I can think of though, and some of them may sound ignorant/condecending, but please don't think I'm trying to be either of those - I'm just going off what I know and what I know have been issues for others in the past. I've been a member of Slimming World for a long time, and I've seen these issues most with members whose losses tail off sometimes.
Have you stuck to the same meals/foods/snacks for the last 6 weeks? It might be worth changing the kinds of foods you are eating and see if that gives you a boost?
Do you drink enough water during the day? Not counting tea/coffee, but you can count water with squash in (assuming you aren't restricted with those) Try to make sure you drink 2 litres throughout the day.
Has your exercise increased recently or have you been doing the same things for the duration of your losses? Sometimes the increase in exercise can have an effect on your losses because of the fluid in your muscles.
Have you stil got lots to lose, or are you close(ish) to your target? The closer people get to their target weights, the slower the weight can come off.
There also the fact that yo've lost so much in such a short time that your body has adjusted to your new diet more and your losses may just be slower now.