Sounds like you have mineral deposits or debris in your spigot. So the next thing you need to do is to take off the bottom of your spigot and check the screen that is in the little spigot attachment just unscrew it like you would a light bulb ( you may want to use pliers or a wrench if you do be sure to wrap a dishcloth around the spigot to protect it from damage via the teeth of the tool you use) it should come off with little to no resistance. Check the water flow now with the spigot tip off your faucet , is the flow strong now? If not you may want to contact a plumber or replace your faucet. If so than look into the piece that you have unscrewed if there is visible debris than you should be able to tap the head upside down in your sink and it should fall out. If it is mineral deposits you can use a commercially available solution to dissolve them (such as C.L.R.) or you may want to use a common household fix for metal mix 1/2 cup vinegar and 1 quart of water in a bowl or bucket then soak your spigot screen for fifteen minutes then scrub with an old toothbrush. The solution for plastic though is 1/2 cup hot water to 1/2 cup vinegar and allow to soak for one hour. After you have thoroughly cleaned the screen and replaced it and the washer in the spigot than you need to reattach it just as you did when you removed it taking care not to cross thread it when you screw it back in. If this doesn't help than you may need to replace the screen.