Positive OPK on CD6

Meghan
So, I've read that having a positive OPK is possible this early, but it just doesn't seem right. My periods usually last 6-8 days with an irregular cycle lasting anywhere from 28-38 days. 
I had a miscarriage in April, started my first period 28 days after the first day of the miscarriage. Then started my period 32 days after that first cycle back. Both were "normal/heavy" cycles. Im actually on day 6 of my second cycle back. 
Anyways, we are so excited to start ttc again since we got the all clear from the obgyn. I started taking the clear blue easy digital opks again yesterday (the first time we used them I got pregnant that first month after 6 of trying). Yesterday was negative as I would expect. Today it came back positive with a solid smiley face. 
It just seems way too early to come back positive when I usually have a longer cycle. Going to test again later today. Just confused. Have any of you had a positive OPK this early and it be real? I'm charting my temps, so we will see if they coincide!