What could cause a sore throat, swollen tongue, mouth sores, red bumps all over my tongue and the back of my throat and extreme fatigue besides strep.

Seasonal flu. is very common viral infection. Usually the condition resolves on its own with home care. Drink water and get a good rest. NSAIDs (e.g. Aleve, Advil) or Tylenol (acetaminophen) are also recommended every 6 hours. If concerned, see your PCP for examination.
Pharyngitis. It sounds as if you may be suffering from acute pharyngitis (infection of the back of the throat). The majority of the infections are caused by viruses but they can also be caused by bacteria, such as streptococcus. Not only do they cause pain in the throat, but they can cause other symptoms as well, such as fever, chills, headaches, generalized bodyaches (including back pain), cough, and fever.
See your MD. It is good for you to be diagnosed properly. It may require some lab test to determine the causative factors of the condition presented.
Any other infection. Most likely a virus but there are also other bacterial infections besides strep that can cause these symptoms. If strep has been ruled out then i would watch for a couple days and if not improved return for a further work up.