I framed the walls with 2 x 4 studs. The exterior of the house is wrapped with Tyvek. I insulated the inside with reflective insulation "Ayrfoil" and with R-13. If I use 1/2 inch sheetrock will I have condensation build up behind the walls between the bays?

I have a closet that is on an outside wall. It has always been cold in there and I keep a towel on the floor to keep the cold air in. I recently pulled the framing and insulation off the wall in the basement and found that quite a bit of moisture is building up. I then took everything out of the closet and noticed mildew and that the walls were wet. Not knowing what was going on I took two pieces of the plaster out to try to get behind it. It is insulated with a vapor barrier. I covered the plaster holes up with plastic for now and have noticed there is a lot of water on the inside of the plastic that is running down to the floor and through the floor to the basement wall. What can I do to fix the moisture problem in the closet?