First, thanks for reading. 
A little background story first. I’m a 28 years old woman and up until about a month ago, I have NEVER worked out/exercised in my life…on a regular basis, that is. Sure, I’ve used treadmill, went for swimming, aerobic, all of those just here and there, but not on a consistant basis, whatsoever.
And about a month ago, something struck me and I decided to dedicate myself on a regular workout from that point. Since then, I watch what I eat and exercised EVERY SINGLE DAY for about an hour - 30 mins yoga and another 20 mins elliptical machine.
After about a month of everyday workout as above, I skipped exercising for two days straight due to my busy work schedule, and boom! The next morning, I couldn’t get up; I threw my back out! It went gradually better over the course of past week and now I’m all better, but as Im about to start exercising regularily, I’m so scared of a possibility of throwing out my back again!
First and foremost, what do you guys think was a cause of this incident? Did I work out too hard everyday all of sudden after 20 something years of practically no exercise?
And secondly, how often should I exercise from this point? Every other day or so? Can I at least do light stretching/yoga everyday?
Thanks for reading a long post and your answers in advance! 