You could be pregnant still. Wait a few more days and take another test. Sometimes people don't get a positive until 17 dpo.
No, you are not pregnant, and you can't predict it so early. It's not like that. You've to wait for some more time to know about it properly.
Having a light spotting is not an indicative of pregnancy. Which is also confirmed with your pregnancy test. So be calm relax and enjoy you r not pregnant:)
Sounds like you could be pregnant !!! You should go to the Dr and get a blood test...good luck