I am exercising and doing slimming world. My first week I lost 5.5lbs then ramped up the exercise and in 2 weeks I have lost 1lb! It is really disheartening but I can feel my fitness has improved. Can you do things now that you werent able to do before? Focus on that, if your body is getting fitter then sooner or later the weight will start moving again. You may well be building muscle instead. I know whenever I exercise my weight loss virtually stops, my mum said after she started regularly exercising her weight didnt really change but she noticed her body firming and toning up loads and she felt good for it.
I know its really hard, I have hit the brick wall with my motivation this week after my 0.5lb loss per week and eating really well (rather than the junk food I crave!), but I am trying to tell myself that if I am fitter, it doesnt matter so much about the weight as I know I am becoming healthier and the inches will start shifting as a result.
Also, if it is your period you may be struggling more to lose it, if you are wearing different clothes to when you last weighed yourself, if you weigh yourself at a different time of day - I can put on lbs in the daytime but it disappears overnight. I always weigh myself butt naked as soon as I get up, before I have anything to eat or drink so I get an accurate reading, as otherwise my weight fluctuates like mad during the daytime.
It sounds like you are working really really hard so try not to get yourself down as it will pay off. Measure your inches and see if it starts coming off there instead and make sure you drink loads of water and eat enough to burn or your body may think its starving and start storing the calories.
Hope you feel better about it soon xxxx