Im on my second round of antibiotics called bacterium, & my pain/having to pee feeling still will not go away. what should i do?

Need new antibiotic?: I think you mean Bactrim®, i.e. sufamethoxazole plus trimethoprim. Although commonly used for urinary tract infections, many bacteria that cause UTI are resistant to this antibiotic. Contact the doctor treating you about a different antibiotic, such as ciprofloxacin or levofloxacin. Probably you should also have a culture test to learn the exact bacteria causing it and the best antibiotic.