Yep, you really need to consult the CAB and they should put you in contact with a debt advisor etc... You can also telephone the National Debtline at any time - http://www.nationaldebtline.co.uk/
- they should be able to offer you advice whilst awaiting to speak to the CAB.
The website www.mymoneysteps.org
is a service run by the National Debtline, and it should assist you to work out what options you have in your current position and the pro's and con's of each option available to you.
Then there is the CAB advice website at http://www.adviceguide.org.uk/
and the Direct.gov.uk website offers a lot o advice at http://www.direct.gov.uk/en/MoneyTaxAndBenefits/ManagingDebt/index.htm
But overall, the CAB ar your best option for giving you plain and simple to understand advice.
As far as im aware, an IVA, can, in a lot of circumstances, be a very bad option, so its best to get advice from the professionals before doing anything further at all, if you feel you are at the point of going don the IVA route.