Help- my turkey defrosted too early!?

I bought my turkey last evening (Saturday) and somehow the turkey was not put in the fridge or freezer. It defrosted overnight. It is Sunday morning. I will not be cooking the turkey for Thanksgiving until Thursday afternoon. The turkey is 12 pounds. Should I refreeze? Toss out? Let it sit in fridge until Thursday??? I think sitting in the fridge for 4 days is too long. HELP! Thank you.