That's totally normal! Many low-carbers I know - including myself - experienced that for the first week or two (some for even longer) because our bodies weren't used to consuming so much fat. I'd suggest dividing your high fat consumption evenly over the course of your day instead of eating the majority of it at one or two meals. When I first introduced bulletproof coffee into my diet, I would have to run to the bathroom an hour later every single day that week! But eventually, my body got used to it and I was able to consume 40-50g of fat at every meal without a problem. Good luck!