CD15 and heavy spotting?

Jennie
I'm on CD15 and just started bleeding red- more than spotting but less than my normal period. No signs of ovulation yet- I normally get slippery CM. Mild cramps. 
​I got pregnant in February (lost my baby the end of April). When I ovulated that cycle no bleeding at all so I don't think it's implantion bleeding. 
​Thoughts? Never happened before!