My 3.5 year old son has had a fever since Monday afternoon. Peaked at 105 Wednesday morning. I took him into urgent care, and he tested negative for Influenzas A and B, as well as for RSV. We were told it was a flu-like virus. Today (Thursday), he had a low grade fever controllable by ibuprofen and Tylenol. At midnight tonight, his fever is about 104.5 underarm, and 20 min later is at 102.6. Should be bring him back to urgent care, which does not open until noon?