Check your agreement, no agent wants to sell a home when the seller is not motivated.
Have a talk with the Agent as to why the change of heart.
You should be just fine.
Remember, in CA as long as you dont accept any offer and sign you should be fine, unless you signed an
agreement that was not standard. Where the contract said, as part of the listing agreement that if you listed at $ XYZ and you got an offer, you had to sell.
REALTORS can't practice law, unless we are licensed to do so. We can discuss business matters in general terms, but we cannot make specific legal recommendations. The law of agency governs listing contracts. See: http://en.wikipedia.org/wiki/Agency_(law) for an intelligent, non-legal discussion.
It is hard to act as someone's agent if the principal doesn't want an agent or doesn't want a specific agent. Courts have generally recognized that agency is easily terminated with written notice. That doesn't mean hassle free or without cost. So now, here come the dreaded words: "You'll have to consult with a real attorney to find out what the practice and likely outcomes are in your local area."
If the agent hasn't done anything on your behalf, nor spent any time or money, you MAY be able to get out of jail free, but not always. Get some help. Soon.