How Low is Too Low?

I have been tracking my food with great accuracy in the last week or so. I was looking at my diet tracking software last night and it said that 2100 calories was my target. All this time I thought I had to get under that in order to lose weight. But I guess much lower than that and I won't lose.

Arrggghhh, why does this have to be so complicated?

So today I looked online to find out if I wasn't eating enough for weight loss. Well the experts are all over the place on this. I found one website that said for my weight I need to consume 5400 calories to maintain my body weight!!! WTF!!! at that many calories I could eat mcDonald's every meal of the day and still lose weight!
I think I might need an expert.