I commend your fighting spirit, but you really need to think long and hard before doing a postbacc/SMP. You need to sit down and factor in the cost of a postbacc/SMP, the time that goes into a postbacc, and the time and cost of hopefully getting accepted your first time around, which isn't as easy as it sounds. Then on top of all this you need to factor in the cost of DO schools, most of which are private, interest accrument, the crummy pay during residency, tax deductions and a 10+ year loan repayment that will cut into your salary.
Finally, you need to factor in: are you comfortable being a DO? I am very happy with the route I have picked and am more than comfortable talking to patients about why I chose DO over MD. are you?
Anyways after all this nonsense if you really want it? Just do it. Don't let me or some other sdn nobody tell you how to live your life. GL mate, hope I catch you on the flip side