Welcome to healthcare Magic!Scarlet fever
is a very sickening disease and produces lot of morbidity.
It is unfortunate that you did not do well with antibiotic Penicillin. make sure you take the antibiotic and painkillers as strict schedule as advised by the doctor. You should be well soon I hope.
Make sure that you have rest, liberal fluid intake and received good nutrition.
It is good that you chest Xray is clear. You should follow cardiologists advice for the cardiac stress
findings in your ECG.
You should keep a positive attitude, should not get depress like that.
The disease will fade out in the days to come.
I hope the advise would be informative and useful for you.