I agree - get some help from others. This sounds like a big event and there is nothing wrong with asking for help, even for small things. You don't need to do everything yourself, and everything doesn't have to be perfect either. I think sometimes when my "perfectionism" rears it's ugly head, I get more anxious about failure, etc. Try to enjoy it for what it is supposed to be - a happy time. And again, don't try to be superwoman!
remember - you're NOT losing it. It may seem that way, but you're not. You're just stressed!