Did you or have you pre-approved for your mortgage? I know a couple of people who have lost out on The House they wanted to buy because they did not get preapproved. The other people who put in an offer did pre-approve and the owners went with their bid.
You most definitely have to be pre-approved for a mortgage loan before you go house hunting. How do you know how much you can afford without a pre-approval? What sort of price range homes are looking at when you don't even you can qualify for them? Submitting an offer without a pre-approval is not attractive to the sellers so they are likely to chose another offer that the buyer has been pre-approved. Your agent should make sure that a lender runs your credit, check your income and debt, and issue you with a pre-approval letter before you start looking for homes.