The loan amount was what your lender qualified you for (amount you qualify due to your current income and expenses etc. that they calculate what mortgage payment you can comfortably repay monthly ) in conjunction with what you offered on the home you'd like to buy.
The FHA appraisal is an independent appraisal of the appraisal's opinion of the actual value of the property you are going to purchase, as of the day he/she appraises it. The bank usually will not loan more that the independent appraiser's opinion of the value of the property. So if you still want to purchase the property, you will have to come up with the difference from what the bank will lend you on it and what it costs, or re negotiate with the seller to lower the purchase price to the appraised value. Or, if you have an appraisal contingency, walk away.
Hope this helps.
Only other option is to appeal the appraisal first with the appraiser, which means someone needs to provide the appraiser with accurate Comps (comparable homes) that have sold in less than a year and within 1 mile of the property in question. Last option is to appeal to the lender if the appraiser will not work with you. There are no guarantees in this process and it is time consuming. Most people work it out or terminate the transaction.