My ds is almost 10 weeks old and has got into quite a routine of feeding and sleeping at 7pm, then sleeping till about 2 or 3 am. I want to start excersising again but can't be bothered don't want to express and get him used to bottles. I want to start exercising and go swimming to lose a bit of baby weight. AIBU to go swimming (out for about an hour and 15 mins in total) without any back up milk for the baby?