randomly last night around 9 my hands started swelling up, and my elbows were itchy. this morning i woke up with swollen hands, swollen knees, swollen elbows, and some itchy spots/hives on my arms and legs. i have a slight cold that i ve been having for about a week now, but in the past 24 hrs i ve only taken one benadryl. what could be going on?