Weight flucuating

If you only just started exercising this much, then I know for me at least exercise makes my weight fluctuate a lot more than if I don't exercise. When I started logging my daily weight I went to the gym almost every day doing a mix of cardio and weight lifting. I've stopped doing that for the last few weeks for a number of reasons (I plan to start again when I go back to uni in October), I now only do walking, and a couple of weeks after stopping my weight suddenly stopped fluctuating. My weight loss graph used to look like a mountain range, now it's flat for a few days, then I lose a bit, then flat for a few days, then I lose a bit, etc. So if you've just started exercising that might be it.

If you've been doing a lot of exercise before then it's probably not that. If you're getting close to your goal weight, that might be it. Or even if you're just around your period it could be that.

I'd also say to be careful of going 200-500 calories below everyday, especially if your calorie goal is quite low (I don't know how much you're eating, your diary is closed). Remember, it's a goal, not a limit.

Maybe the increase in exercise is doing it, then. I know it would to me if I started exercising that much more. If it worries you you could log your weight every day in a spreadsheet, then you can see exactly what's happening, and I think it makes it easier to see what the general trend is. A few weeks ago I thought I hadn't lost anything for ages because what weight I had lost had got lost in the fluctuations. Then when I looked at the logs I realised I'd actually steadily lost 1lb/week.

You should try not to drop below 1200 net too often, especially with that much exercise. Maybe try calculating 80% of your TDEE, that's what a lot of people recommend. You might be able to get away with eating much more calories and still lose weight. Eating too little can slow weight loss.

Total Daily Energy Expenditure, the average amount of calories you burn in a day. Google it, there are a load of sites out there that'll calculate it for you. When choosing your activity level, either include the exercise you do and don't eat your exercise calories, or set it to sedentary or light and eat them back. Once you've found your TDEE, 80% of that is usually what's recommended for losing weight.

When I get stuck, I increase caloric intake to what I should eat in a day for 3-5 days while continuing to exercise and drink water. then I go back to 1200 calories - then I start losing again. Works every time for me.