How long has this been going on? If more than a couple of days, go back to doctor. You might need a referral to a urologist. I don't know why they would give you antibiotics if they found no infection, it makes no sense to me. If you have had an infection which has irritated your bladder, your bladder may have remained sensitive even if the infection has been cured. It is like a mosquito bite which keeps feeling itchy. You have to stop scratching it - ie stop going to the toilet when your bladder complains. Drink a lot of water and when you need to go, lie down and relax, breathe, think about other things, anything to stop giving into the urge (at least temporarily). Cranberry juice is also recommended for bladder inflammation, but check if you can drink it with your medication. Try to fill your bladder up, but not go. Eventually the "itch" will subside (assuming this is just a bladder infection and not something else - don't delay going back to doctor if this continues). Good luck.