Holy Cow! This sounds to me like a severe allergic reaction to me. You need to see a doctor RIGHT AWAY. Why have you not shown/told your parents? They need to know.
Well the results of the strep may be negative, but you still may have another bacterial or viral infection.
You need to see the doctor again, You may have an illness called mononucleosis sometimes referred to as glandular fever or the kissing disease. The infection is usually caught from kissing.
If this is the virus mononucleosis, unfortunately antibiotics will not help.
You still need to see the doctor to check your ears and if there is a bacterial infection, your doctor will prescribe an antibiotic, or an antibiotic ear spray.
You do need the right diagnosis, as it may be measles or German measles.
Have you been scratched by an animal over the last few weeks? If so, this may be a bacterial infection from the scratch and you would need an antibiotic. So do tell the doctor if you have been scratched, even if this is by your own pet.
For the itching you can buy some calomine lotion or calomine based cream from the pharmacy. Natural yogurt will help to cool down the heat and reduce itching. Have cool showers to lessen the itching. Try not to scratch, because this will leave scars.
For the blocked up ears and nose and to loosen up the congestion, do steam inhalations.
To do a steam inhalation, boil up a kettleful of water and pour this into a bowl taking care not to get scalded. Put some Vick or olbas oil or a few drops of any other menthol oil that you have. Bend your head over the bowl and cover your head with and the bowl with a towel. Breathe in the steam for 10 minutes and try to do this 4 times a day.
Drink plenty of fluids. A hot drink with freshly squeezed lemon and honey to taste is really good. Get some medicated lozenges and use as directed on the packet. Make sure that you do follow the instructions on the packet for safe use. You can only use so many within a 24 hour period.
If your chest is congested, you can apply some Vick to your chest, back and throat to help to relieve the congestion.
Do the steam inhalations for as long as required.
Stay at home and away from other people until your spots are healed.
Wishing you a speedy recovery.
I feel a doctor would be the only person to give you a cause for this. Im suprised they havent. It sounds like your allergic to something pretty bad. Maybe try taking a look at what your eating on a daily basis and try and trial an error.