Is this a new faucet? Has this condition been developing over time or was it immediate? Is the water pressure good in other locations? Many new kitchen faucets, mine included, so I am working this problem myself, have quite low flow rates. Any debris in the water will reduce flow and pressure. Pull the aerator on your faucet and clean it. Pay attention to the orientation of parts when you disassemble the aerator. Also, I have seen them with a cone type orifice that really restricts flow. Your faucet may have one of those as well.

One other thing to try - again if it's a new faucet - was the stop valve opened back up all the way?

If it's an old faucet, there might be a kink under the sink or there might be buildup in the pipe. Or even worse, the opposite, a leak in the line so the water's not being pushed through to the kitchen very well.