please...what next

I miscalculated my finances and when I went to the bank today I was -$300.02. Great. And I just realized that the drycleaning I picked up last night didn't contain the bridesmaid dress (that I really like) that is a $250 designer dress. Just realized that now. Of course I have no proof cause the drycleaners takes the ticket back when you hand it in. I am so freaking close to just complete mental nothingness, why do I feel like I can't catch a break? I just am so unhappy right now i don't know what to do with myself