You might have a yeast infection, it would cause the discharge and the burning sensation, but it don't think it would cause you to be a week late for your period,
you could be late because you're stressed out thinking you might be pregnant...By the way you could still be pregnant, what you two are practicing is not birth control and you can get pregnant using the withdrawal method, and sometimes it can take time before a pregnancy test is positive.
Go to a clinic, find out if you have a yeast infection. If you do, once it clears up you'll be feeling better physically and your sex drive might just come back on its own, and if you find that you feel to dry during sex, use a lubricant...That's what they're made for!

and start using condoms or some form of birth control, you are playing with fire going the route you two are.