Xiggy isn't even started D: I feel like crying I am loosing it.
I felt that way about a month before the con last year. Crying might help your stress, and help you calm down, but you'll be fine, I promise. I haven't started a lot of my cosplays, either; heck, I hardly have any idea who/what I'm doing. Just take it a day at a time. I'm sure you'll make a great Xiggy; just take it piece by piece. Before I make/work on a cosplay, I make a list of things I need to do/make, and sketch out the designs, and such. If you do that, I think it might help you feel a little better.
The only cosplays I have even remotely closed to finished are the ones I did last year. Don't feel bad! Ven is giving me quite a good scare, too, but I know that, if it's meant to be, and I stay dedicated, he'll be finished in time.