I had my last cycle thanksgiving of 2011 while on the Mirena I had sex a day before removal which was March 16,2012. Then had sex again the 19th. I spotted pink today and have been cramping. One negative HPT 2 weeks ago.

Yes, in some situations you can ovulate without having a period. Since the hpt was done 2 weeks ago, you may want to try another one. It could be that your body is still adjusting, which can take some time for some women, or it could be due to a period about to start, or it may be due to pregnancy.