Jonty, starvation mode is yet another weight loss myth.
There are perfectly acceptable, even doctor-supported diets of 500 kcals a day for people who need or want to lose weight fast. The only issue is getting all the necessary nutrients into those 500 kcals (and in some cases, not getting hopelessly constipated!).
The idea that eating some more for a while will 'kick-start' your metabolism during a plateau is also a weight loss myth, as far as I remember.
If your loss stalls for more than three or so weeks, start thinking about whether you've eaten much more salt recently (possibly causing you to hold onto water), or whether you've been tracking your calories inaccurately, or whether you've just reached a point where you've lost so much weight that the calories you're now eating are more or less what you need in a day and not a significant deficit.
And bear in mind that the scale going up and down by a few pounds each day is food/water in your system. Only ever weigh yourself first thing in the morning, before drinking or eating, after peeing (and other excretions), ideally naked and if not, with exactly the same weight of pyjamas on. Consider whether you've gone for a number 2 recently. If not, then that's probably your weight loss being masked right there.
If you're breastfeeding, Titsalina, I would wonder whether maybe related hormones are somehow affecting your water retention or something, beyond just what you need to produce milk. I don't know enough about that just yet though (med student). 
I'm 0.3 kg heavier than I was at weigh-in yesterday, but I'm sticking to my calories so I'm not worried.