Reassurance?!

Ok mommas, I had a M/C in January 2014. Had a beautiful, healthy baby in June 2015. Now 6 weeks 2 days and cramping like crazy!! I had no symptoms with the very first pregnancy and every test was super faint. My tests now are really dark and I have sore nipples and nauseated at night. Any body else just feel really crampy like AF is going to start?! 
Please reassure me that I'm not losing this baby too.