Mine started around 12 weeks the second time (which I know it can be earlier second time around) so it definitely isn't too early. If you go see a Dr/Phsyio they'll be able to diagnose you more clearly, if it is SPD it is better to be doing all the right things now in hopes it won't get too bad in a way to prevent irritating it further.

Goodluck!

*hugs*
Cailin