The reason for this is that your bankruptcy shows up on your credit report in the equivalent of flashing red lights and huge neon signs so that potential lenders are aware that you have filed. And the reason for that is simple - you are now considered a much greater credit risk, and loans are placed and interest rates determined based on the amount of risk that the lender feels he needs to take with your loan.

The first thing you need to do is to make sure all of your debts have been fully discharged in your bankruptcy. If the proceedings are still taking place and it is not complete yet, you very likely have a very poor chance of securing a loan, since that is just about the highest risk factor that can be considered by a lender.