GA SMA ALTDEV DSNDED BELOW FAF ALT BEFORE REACHING THE FAF.

Narrative

I WAS ON VOR AIRWAYS WHEN ENRTE TO C09 FROM 3AR. CHICAGO APCH CLRED ME DOWN TO 2500 UNTIL INTERCEPTING INBOUND COURSE. THIS ALT PUT ME IN THE MIDDLE OF A CLOUD LAYER WHERE SOME ICING HAD BEEN RPTED FURTHER N. WHILE IN THE LAYER I RECEIVED A SERIES OF RADAR VECTORS AND WAS CLRED FOR THE APCH UPON INTERCEPTING INBOUND. THE CTLR ADVISED ME I WAS NOW 4 N OF THE VOR AND WAS TO CONTACT HIM TO CANCEL IFR WHEN ABLE. DUE TO THE RADAR VECTORS I WAS TEMPORARILY DISORIENTED AND BEGAN TO THINK I WAS S OF THE VOR AND BEGAN MY DSCNT SINCE 4 DME WAS THE FAF. AS I WAS DSNDING I BEGAN TO QUESTION MYSELF AND DISCOVERED I HAD NOT PASSED THE VOR. I PULLED UP IMMEDIATELY BUT I HAD DSNDED JUST BELOW 2000 MSL BY THAT TIME. APCH GAVE NO WARNING OF DSNDING BELOW THE MIN APCH ALT. ONCE I REALIZED WHAT I HAD DONE; THE REST OF THE APCH WAS FLOWN WITH MUCH MORE CARE AND ATTENTIVENESS. FACTORS CAUSING OCCURRENCE: I WOULD SAY THE OFF AIRWAY VECTORS COMBINED WITH THE FACT THAT I HADN'T DONE A LOT OF RECENT IFR FLYING. FURTHERMORE IT WAS AN AREA I WAS UNFAMILIAR WITH. ALSO I WAS THE ONLY PLT AND I HAVE BEEN TRAINED FOR 2 PLT OPS. I MIGHT HAVE BEEN RELYING ON THE BACK UP OF OTHER PLTS IN PREVIOUS FLTS.