I'm miserable, I have a severe UTI. Got a 3 day course of nitrofuratoin. I'm off work the pain is so severe but I have so much to do I need to be back asap. How long do these tablets take to clear up an infection? Any personal experiences? Also I'm feeling a bit lightheaded, tired and sickly, took the tablet an hour ago. Anyone else have similar side effects? I'm so miserable, UTIs are awful! 😟