No hot or cold water pressure?

We bought this house 1 yr ago. At the time, the only problems we had with water pressure was the no hot water at the kitchen faucet and low hot water pressure in the master bath. Now the problem has expanded, we have no hot or cold water pressure in the 1/2 bath, low hot/cold water pressure through the new shower head, and now the kitchen has lost the hot water pressure it found about 2 months ago. HELP, my husband is not happy in the shower when this occurs.