Severe UTI

I was wondering what a ‘severe UTI’ or bladder infection is. I understand you get symptoms but what makes it ‘severe.’ Im pretty sure I have one due to my urine being cloudy and me needing to constantly pee. I took a plan b about 3 weeks ago and it’s still messing with me and Im still cramping on my left side. I of course googled the symptoms and lower abdomen pain and cramping is apparently a symptom of a bladder infection. I just wanna know if the plan b is causing this stomach pain or if my bladder infection is ‘severe‘ causing this pain. I haven’t had any lower abdomen pain, it’s been strictly cramps on my left side which is why I’m kinda freaking out. I’ve noticed the cloudy pee and need to urine every 5 seconds for the past 3 days now.