I don't feel well...looking for a diagnosis...

Unless you have reason to believe otherwise, it’s probably the common cold, and you’re likely running a fever. I find it hard to believe you haven’t experienced that particular set of symptoms before.

I have but never this rapidly. This has occurred within 2–3 hours and I now have chills and very slightly disoriented. I took some medicine but it hasn’t worked. It was just Tylenol (which I have taken before, no side effects). I thought maybe there might be a reason why it is onsetting so quickly.

You could telephone a consulting nurse. If you are a victim (er, customer) of an insurance company, they may have given you a free consulting nurse phone number you could call (typically on your insurance info card), or you could try the phone book or Internet phone reference for local clinics and hospitals, or your doctor’s office.
In general though, ya that sounds like cold or flu and sometimes I have had symptoms seem to appear suddenly, especially if I’ve been distracted by work or busy-ness, haven’t eaten lately, not enough sleep, or have been out in the cold outdoors and then come inside.

The Mommy or Granny rule is that if temp. is c. 101 or higher, call the Doc. Also if chest cough starts. Clogged sinuses will cause headaches; flu——> joint aches and a general crummy feeling all over…Primary desire is to huddle under quilt, sleep, drink water or juice and occasionally stagger to toilet.

Probably a brain cloud.