2001 Chevy Silverado power steering and brakes

Truck brakes and power steering were working fine, I was at a red light started to make a left hand turn could tell very quickly the power steering was very hard to turn pulled into parking lot and brakes were not working had to push very hard on peddle to stop. Checked fluid level on powersteering pump it was a little low but still in operating range, brake fluid level was just below max level. Could not find any leaks no movement on belt pullys, belt felt tight, no noise or warning lights came on. Thanks for any help, Jerry