Does your fiance have insurance? If so, he can start filling out the paperwork to have your child on his insurance now. This paperwork generally has to be filed before the child is born.
If neither of you have insurance, tell your doctor and s/he will tell you how to sign up for medicaid/medicare. S/he can also direct you to information on how to get WIC and other financial help, should you find you need it.
Don't worry too much about not having insurance. Many people in the United States do not have health insurance, but are still able to seek adequate prenatal and postnatal care.
While we're on the subject of prenatal care, if you have not started going to regular prenatal doctors' visits, please, PLEASE do so immediately. Doing so will help to insure that you have a healthy baby and a healthy pregnancy.
And hon, you are not a failure, regardless of what anyone may think.