Hey I had a similar nasty start with my M&P 9C. I noticed two things. First was it really favors a 6 o'clock aim position. Aim a few inches below your kill zone and that should bring your groups up on target.
Second is really hard to explain and it had to do with grip. The contoured grips are REALLY nice in "my" hand - but much different than Glock, PPS, Sigma, PPK's that I shot normally. I chock it up to muscle memory and had to simply "adjust" to the new type of grip. After about 400 rounds or so though I grouped where I wanted. Maybe change your backstrap?
Take 'er slow...start fresh like you're just learning to shoot all over again. Stance, breath control, site allign, trigger pull, follow through one shot at a time. After each shot, assess and adjust until you get consistent. Then slowly ramp up your speed to where you are with your other guns.
It's a honey of a gun IMHO - but yeah it did take me off guard at first.
Good luck!