Unfortunately, unless an offer is in writing, and signed by both parties, nothing is binding.
Real estate is practiced differently depending on where you are, so I'd ask the agent (or a different agent) to explain how it works in your area.
Agents don't "accept" offers - sellers accept them!
If the agent implied the seller would consider your offer, or went as far as to say your offer would be accepted, the fact that it was only verbal doesn't secure you the house.
Also keep in mind that an offer is more than just a number - were all of your terms clarified?
I think your agent should do a better job of walking you through the steps necessary to buy a home.
If you do not feel you're being properly represented, ask to speak to the Broker.