PA28 PLT DSNDED BELOW CLRED ALT.

Narrative

I WAS AT 8000 FT MSL WHEN CTR GAVE ME PLT'S DISCRETION TO 5000 FT. THIS WAS MY FIRST TIME BEING SOLO IN IMC SINCE MY IFR CHK RIDE AND I WAS UNDER SOME STRESS BECAUSE OF THIS. I BEGAN A SLOW DSCNT (400-500 FPM) OUT OF 8000 FT. SOMEWHERE DURING THIS TIME; I STARTED THINKING I WAS CLRED DOWN TO 4000 FT. I BROKE OUT OF THE BROKEN LAYER SOMEWHERE AROUND 5400 FT MSL AND CONTINUED TO SOMEWHERE AROUND 4500 FT; WHEN ATC INSTRUCTED ME TO CLB AND MAINTAIN 5000 FT. NOT REALIZING MY ERROR; I THOUGHT IT WAS STRANGE TO BE GETTING A CLB. SHORTLY AFTER STARTING THE CLB; ATC GAVE ME THE INFO THAT I WAS ONLY CLRED DOWN TO 5000 FT; BUT I WAS NOW CLRED DOWN TO 3000 FT. SINCE I WAS IN VMC AND RATTLED BY THE SIT; I CLOSED MY IFR FLT PLAN AND CONTINUED TO MY DEST VFR. I THINK CONTRIBUTING FACTORS WERE: MY FIRST TIME IMC WITHOUT A FLT INSTRUCTOR. MY ERROR OF NOT CHKING THE ALT I WROTE ON MY KNEEBOARD. BREAKING OUT INTO VMC CAUSED ME TO LET MY GUARD DOWN AND RELAX (THINKING HOW WELL MY FIRST IFR SOLO TRIP WENT). PROLONGED TIME IN WHICH TO DSND THE 3000 FT IN WHICH I BECAME BUSY SETTING UP FOR THE APCH. A LONG TIME VFR PLT GETTING AN ODD ALT ON A WESTERLY HDG.