Weight loss

I am 8 weeks 3 days pregnant and in the last 3-4 weeks I have lost 6lb. I usually find it difficult to lose weight and haven't been trying to. I have had a lot of nausea over the last few weeks and have been put off a lot of food. I've been sick about 3 times but other then that i'm ok. Has anybody else lost weight and should I be worried? Thanks :-)