Why did flu raised my dystolgic bp by 10 points? 130/90? Previously 120/80

Physiologic. Your blood pressure will fluctuate during the day regardless of your state of health. An isolated increase shouldn't be of concern; more concerning while ill would be a lower blood pressure. Continue to monitor it for the next few days and see if it returns to your normal baseline, but don't be worried about 130/90 unless you are pregnant; if pregnant, talk to your doctor about the lower number.