I have a question regarding purchasing a house. Assume the bank appraisal value is lower than the contractual price, and the seller and I cannot make agreement for a new price, will I lose all of the earnest money if I decide not to move forward.
You should read the provisions in your offer and any counteroffer that was signed before paying the earnest money, but generally if the appraisal comes in low, the price has to be adjusted. If you can't get a mortgage (because the appraisal is too low) the next guy usually can't either.
Unfortunately without more information (the documents that were signed and the locale, to know which laws might be applicable) I can't tell you with certainty that you'll get your earnest money back.