At the moment, technically you are not insolvent so bankruptcy might well be queried. However, if you miss payments on some of your debts the situation will change so that is what you should do if you are certain bankruptcy is the best solution. You ought to get some free independent advice before taking that step - your local CAB or other free debt advice agency should be able to help, or ring CCCS.
Don't worry about having bought something on credit (unless it is an enormous expense!) - you didn't realise when you bought it that you weren't going to be able to cope financially.
It's possible that the car will be at risk unless it is essential for work (eg travelling to & from work at unsocial hours when there is little or no public transport) unless someone (friend or relative) could afford to buy it & let you go on using it. Again, you need advice.
Whether you will have to pay for 3 years depends on your income & the assessment that will be made of your reasonable domestic expenditure needs. If you are deemed to have a surplus of £20 per month or more (i.e. income £20+ above assessed expenditure) then a 3 year payment will be set up.