No water pressure in the house?

I just changed a sink in my guest bathroom and now I have no water pressure in the hole house . This is how i did it 1st I turned off the main water out side to the house then I left the water running till no moe water was coming out of the sink then I turned off the valves under the sink because I replaced them as well then I replaced every thing turned on the main then turned on the valves under the sink . Now I also replaced the hoses and one of them is leaking so i have to take it back but I just turned off the valve under the sink and it stopped leaking but now my shower ,toilet & all sinks have no pressure & the shower starts out dripping then in about 5min will work its way up to were you can finally shower what should I do ?