Firstly well done on having made a decision to get fitter and lose weight! Secondly woah!!! You don't say how much exercise you did if any before 8 /9 weeks ago or just how sedentary your life was or what you do for work etc, but i think your knees and ankles are complaining about your amazing increase in exercise. They still have a number of stones to carry and I think you need to rethink your exercise programm to reduce the joint strain. It could get worse if you continue but I wouldn't recomend more rest days, gentle exercise should be part of every day. You need a change in type of exercise to less weightbearing and including other body parts, and including some cardio training BUT keeping it gentle to start with. Swimming, with crawl to reduce repetitive bending and straightening the knees would be OK. General exercise in water including walking also reduces the weight on legs but water resistance can be used for arm strength. Core stability for trunk, realy gentle first would also be good. It depends a bit on what you like doing and how much time you have to do it, your chosen sport must fit in with every day life or the excuses start You probably need some advice from a good professional who could see you, assess your needs and help design a sensible progression over the next months and avoid overdoing it. You'll have to adress the dietary requirements too and not lose muscle..again consult an expert nearby. Wish you loads of success in the coming year!