My DS is 5 months and around 18 lb and I'm already struggling with carrying him, lifting him, wearing him in a sling each day... my back is killing me to the point I struggle to stand up straight sometimes! I'm slim (115 lb) have never had any strength, although am aerobically fit as I run (pre baby I ran marathons). If I'm struggling now, how will i cope as DS gets bigger?! What exercises can I do to help?? How can I make sure I don't end up with chronic back pain ??