That was an odd turn to take - firstly, I've never heard of that.
I once had a period come as early as 14 days. I don't think I'm infertile because I'm 18 and this was like 3 years ago when my period was still super irregular (love the late bloomer phase). I don't think it is a sign of infertility however I do see where you're coming from because of the ongoing hormonal imbalance in the menstrual cycle but it could just mean that you ovulated earlier than your last cycle and the uterus lining had to shed earlier - like a cascade.
If you're very worried, please do see a doctor and get some sort of reassurance.