Hi, so, you are suffering from urinary frequency and urgency. Your problem need proper investigations. Cause may vary from a simple urinary tract infection
or a new onset diabetes which can be totally cured/ controlled by a course of specific antibiotics ( chosen on the basis of urine testing report) or appropriate treatment of diabetes
. It can be due to more complex uro-dynamic problems. If you are not in a hurry please check your urine DR, urine culture & blood sugar & show it to a doctor for appropriate treatment. If these test are normal you should consult a urologist
for more detailed investigations. Meanwhile for your concert; you can probably take help by avoiding tea, coffee, cola drinks or any other caffeinated drinks on the day of your concert & limiting your water intake to minimum. But this of course is not a long term solution. You must go for investigations. May God help you.