Is this the flu or just a really bad cold?

You have the symtoms of microplasma pneumonia, a.k.a. walking pneumonia. It wont go away on it's own. It will linger on and on, and run you down. You need to get on antibotics. The best is the "Z-pack". It's a 5 day dosage that really knocks it out. This is a bacterial pneumonia, not viral. So meds are needed asap. If you can't get into your dr right away, get into a med stop, or urgent care type of place. Get TONS of rest and drink water - not gatorade.