well, I was in the same situation as you at one stage, but i left it out in the sun, than i freezed it and i didn't get sick,when i ate it later on in the week. But before you refreezed it did it smell off. like a really horrible smell, cause if it did you might. but if it just smelt like normal shirmp before you refreezd it don't worry to much, you shouldn't get sick from it.
