Think it would be a good idea to stay in the water and find your way back to WindClan by going around the lake.

From Wikiventure

Although you are cold, you take your chances in the water and begin to make your way around the lake. Sometimes when the water gets to deep, you travel along the shore, but you are too afraid to loose the lake that you don't want to even get out of it. By dawn, you find yourself at a rather large stream that empties into the lake.

Now you...

Dismiss the fact that you could be swept into the lake if you fall and decide to risk leaping across.

Try to find another place uphill where you can cross.