Welcome to HCM,
With information you have given it is clear that you have a Urinary Tract infection
and some antibiotic course is given to you along with injection.
Micro-organism that cause UTI commonly are E Coli
but other can also cause and sometime resistant to drugs.
But you have taken only for one day it will take some time before your symptoms go away.
You can take plenty of fluids and craineberry juice.
If urine culture and sensitivity is done you will come to know which drug is most suitable for your infection .
In the mean time continue to take medication, you will be soon OK.