What to expect with radiation treatment after prostate cancer surgery?

Hello, found out last fall that I had prostrate cancer, had operation in September, did a 5 day stint in the ICU, complications of the surgery, pneumonia, blood clot in left lung, along with sepsis, was told in February my PSA was not zero as we had hoped, did a pet scan March and cancer has spread to a lymph node, and decided on radiation treatment that will start in July, did not want to do radiation when first diagnosed, now I have to do it, thank the good lord for insurance the medication price is off the charts. But I cannot complain, was healthy for 74.5 years, my first hospital stay had to be in an ICU. But finally getting some energy and was told the medication will make me feel fatigued, not looking forward to that.