Since you're in California, not Colorado, you most likely signed a CAR form Disclosure Regarding Real Estate Relationships. That form specifies that the Agent can represent both parties BUT there must be knowledge AND consent of both parties and there are specific guidelines the agent must follow when representing both seller and buyer. I would suggest you first have a conversation with your agent's broker and express your concerns and try to make sure you have been treated with utmost care in the transaction. The leading cause of issues between agents and buyers/sellers is failure to properly establish agency relationships. Whether or not you can back out of your purchase agreement is not clear until you have that conversation and the specifics of the contract.
You need to look at the contract. There are quite a f ew reasons that a purchase can be terminated, particularly during the contingency period. This is not legal advice, consult an attorney if you have concerns.
The default period for contingency removal is 17 days in most cases and is designed to allolw the buyer to investigate make sure that they want the property and can obtain the financing to purhase it. I would be concerned if one agent was representing both buyer and seller, because you want someone to represent your interests, right?
I would check with an attorney regarding the comission question also. I can speak for myself but insisting on being paid a commission on a sale that a buyer does not want seems to be unusual.
Why do you want to get out and how much is it worth to you? Debt Free Dave mentioned Dual agency, but he is mistaken. Colorado doesn't do dual agency anymore, it's called transaction broker now. If your agent didn't inform you that she had a relationship with the buyer at the start or in other words if she didn't disclose to you that she was switching to being a transaction broker, then she is in violation of the real estate commission rules. As such, she could be fined, suspended, or lose her license. As such, the threat of filing a complaint with the state real estate commission might be enough to convince her that she needs to deal with this situation in a way that you will be satisfied with. Bad Realtors give the whole group of us a bad name. If she is not following the rules then she deserves to get out of the business. I would need more info to make a better assessment of the situation.
Richard Davis, Broker