My 7 week old DS has started sleeping really well. At night he has been sleeping 7 hours, fantastic (I thought!). Today I took him to be weighed and he had only gained 1oz. Last week he had put on 14oz. The HV has told me to wake him at least 3 times through the night for a feed. when awake he is very alert and happy. Would you follow the advice and wake him or leave him peacefully asleep ? ?