Telling yourself you're stupid won't help.
Neither will panicking. You need a clear head to get through this, and the clear message is that, short term, if you don't keep a clear head you will go under.
The fact that you're acknowledging, at last, that there is a problem, is step one. Step two is through the door of your loal CAB or debt counselling scheme. If you don't keep a clear head at that stage yo won't be able to tell them all the things they need to know to help you get your affairs in order.
Right now you're in the toothache stage of debt management - if you go to the dentist it will hurt, and you'll feel embarassed at the state of you teeth. If you don't go to the dentists though, the pain will only get worse. In this case, CAB or a debt manager is the dentist, so get some solid advice, now.