Wilted Gardenias?

I purchased two gardenia plants from Home Depot about two weeks ago. They were definitely in need of repotting, so I did. I also added one stick of fertilizer and watered each with one cup of water. They've been indoors in a sunny warm spot - and I have a humidifier on all day long. I haven't taken them outside because I'm in CT and it's still quite chilly here. Almost three days after I repotted them, they began to wilt with only a few yellow leaves. The dark green color has now faded to a lighter shade - but not pale. What could be going on? Should I throw them out and start over? Is there anything I can do to revive my plants?