Can I input information on my previous periods?

Hi there, I'm new to glow, but I have been tracking my period prior to this. Last month after I got positive test results, I logged on that day that  I was pregnant. However, it turned out to be a chemical preg. So I then logged when I started bleeding as my CD1. But I noticed then that my previous period data were deleted and my <a href="">period calendar</a> looks like this is the month I ever entered any data. Now I want to input my perious data but am afraid it will delete my current one again. Could you please advise? Thank you very much.