I'm no doc by any means, but I had something similar -- though not as severe -- about 20 years ago. It was right before graduating from college and of course I was up all night studying and finishing projects (not to mention packing to move home and partying

), also working extra hours and it all took its toll. Got a major bug that I couldn't shake.
Took three rounds of antibiotics before any improvement. Then, I was diagnosed as "borderline anemic." (Initially, I think they thought I was anorexic because I was quite thin back then -- under 100 pounds. If they only knew how I l
ove food.

) But, they put me on super duper iron pills for a month, did one more round of antibiotics ... and it was gone. Apparently I had a serious iron deficiency, that coupled with my beat up immune system, just kept me sick.
For your sake, I hope you will get similar diagnosis. Try to stay positive and try (I know it's almost impossible) to not worry. That will only make your body weaker. Good luck!
Thoughts and prayers headed your way.