Hi Emma, and
We do have an Alli support thread here...you may want to ask the folks there about side effects, since you have already purchased the product:
http://www.3fatchicks.com/forum/showthread.php?t=126601
Other than that, just look around! We have so many wonderful, supportive people here.
I had a six month plateau once. Sometimes, your body just doesn't cooperate. But you CAN break through it.
You also might need to start following more specific plan to get your food intake to a point where you'll lose at this point. As we get smaller, our bodies require less food to run, so you'll have to eat less to continue losing. It may take some experimentation to get the scale moving again.

for the amazing success you've had so far. Keep posting - can't wait to hear more from you soon!