What Causes Blurred Vision And Fatigue After A Prostate Biopsy?

I had a prostate biopsy 3 weeks ago. Had the typical blood in urine along with blood in semen. I was told that a few of the Prostate samples taken were higher with cancer than the previous biopsy. About a week ago I went for a short walk up a slight hill when everything got extremely bright, like everything was glowing , I became extremely fatigued, I immediately turned around went back to the house and sat down. After about 15 mins I was back to normal. It happened again two days later while cutting the grass. I saw my PCM the next day . My blood pressure between lying down, standing and sitting was 90 over 60. Nothing unusual with blood andurine samples. Was told to cut my lisinopril in half, to 10 mg. The next couple of days I felt back to normal. Then today it happened again. Just walking up a slight hill, the blurry , bright vision and the feeling of exhaustion. Saw my doctor again took more blood work and urine samples, will get results Monday. This has never happened before, only after the biopsy.