Extreme pain

So last month I had bronchopneumonia and the doctor gave me three types of antibiotics and a probiotic, the following month my period was 5 days late, my period was extremely irregular and heavy.

I’m not sure weather this is related but now my pelvic area, lower back area and upper thighs are in extreme pain, almost like a throbbing pain, anybody know what to do?

This is the first time this is happening