I'm 35, about a stone and a half over weight I'd like to be so have started eating roughly 1500- 1600 Cals per day, doing the 30 day shred DVD (level 1) most days and doing a very brisk 40 minute walk most days. So why do I feel like I am more knackered and my knee joints are about to pop open and spray the walls with cartilage?! Haven't had knee probs before!! It's a real struggle to wake up/get up in the morning as well. I can't be overdoing it can I? would cod liver oil or summat help!?