Hello~I don't think your regular GP will admit you to the hospital for these symptoms, especially without having blood tests done. From the looks of your symptoms, it would appear to me that you are coming down with the flu, and you need to be careful that it doesn't get worse, if you are still feeling poorly after a few days, then a visit to your doctor will probably be necessary.
I hope you feel better soon.
Sorry you don't feel well. It is highly unlikely you would be admitted to a hospital. Your doctor will run some labs and do a physical exam. It could be a virus, mono, or many other things. When heart or lung disease are at work, when severe infections, dehydration, fractures or strokes occur, admission may well be the only option. Honestly, many things we used to do as inpatients can be done much more cheaply as outpatients (and without risk). If you truly need to be hospitalized it will happen, but that would be a rare situation. I would urge you to make an appointment with your healthcare provider.