This is call Acute Urinary Retention. I had this on second pregnancy. I can't urine for days and keep coming back to KKH. There was a blockage on my urine passageway because of uterus. But this is during pregnancy not after that I had it. Idk if this technic help for you. But for me, I did was to be calm, relax, breathing technic, can use bidet to aim at vaginal area, then ill urine. Then ill train myself without catheter, to slowly try urine every few hours. I had a mummy who approach me before just like you and she thought it was only her had it. I refused catheter neither admitted to do it myself so I do at home and train myself.