Seriously comfortable

For the last few weeks, I've had lower abdominal  pain while I urinate. I've been tested for UTI and it came back negative. My doctor says it will pass and to not let my bladder get to full but that's almost impossible. I can't tell when my bladder is getting to full or is full until I need to go to the restroom.. I really want this discomfort to just go away. 
Anyone else going through this and can give me pointers on how you handle it? 
Thank you in advance.