birth control doesn't work for me??

I've tried multiple forms of birth control. the first time I got pregnant I was on the pill. after I had my daughter I got the shot, and wound up with a chemical pregnancy (early miscarriage) after that I tried the Nuva ring and I'm now 37 weeks pregnant-_- obviously I need backup birth control like condoms or whatever, but what is the point of even using something besides condoms if it doesn't work??? I'm trying paragaurd next. any advice? anyone else immune to birth control???? why?????