First off you need to understand bond duration. It is a measurement of interest rate sensitivity, represented by credit quality, coupon (interest payment), and the bond length of time to return of principal. Let’s say you own a 10 Year Treasury Note issued at $1,000 with a 2.5% Coupon. If interest rates for the 10 Year Treasury move +1% or -1%, the value of that bond would like fluctuate -$100 or +$100.
Second, you need to understand how fund flows from large institutions affect bond pricing. The Fed may be raising rates which negatively affects bond pricing, but some investors may feel the stock market is more risky than bonds, or that the Fed is limited in regards to upping interest rates. Those factors would increase flows raising bond prices, lowering yield. Think of prices and yields as a two sides of a teeter totter; one up while other down.