It is really hard when you try to do all the right things and you don't seem to be getting anywhere. Are you BF? if you are then it could be likely that with all the sudden exercising that you've sent your body into a fight or flight mode - it's basically like you body has said 'oh no! she's trying to lose weight and I need those fat stores to make milk' so your body will hang on to it kwim? What you probably should do is keep a food diary and write down everything that goes into your mouth during the day, make sure you drink at least 2lts of water per day and also look online for a daily calorie calculator. Some women do find that their milk will drop off a bit when on a diet so you need to make sure that you aren't denying yourself food if you are hungry - there are loads of other ways to snack healthily and keep your metabolism going. I know weight watchers do have a breastfeeding program if your are into that sort of thing. But if you take it slowly, exercise at a moderate level each day (your DH will be able to help you with that) then the weight will come off and the long term success at keeping it off will be better.