While IQ tests provide very good estimates of intelligence for most people, there are individual cases where the results are highly inaccurate. This can occur for a variety of reasons. Among the most common reason is a lack of familiarity with IQ test items. For example, some of the pattern recognition items that are found in progressive matrices are unduly difficult for someone who hasn’t seen this type of item before.
A second problem, is that some very intelligent people like to ruminate over problems until they are certain of their answer before they proceed. Such people do not score well when rushed. Furthermore, there are some intelligent people who see ambiguities in some of the items posed and this slows their response, causing them to have a lower IQ score than they would otherwise achieve.
There are many cases when a person has achieved significantly different scores on IQ tests administered months apart. We sometimes behave like different people on different days. So, I would recommend that you get some IQ items on line and practice them to ensure that you’re familiar with the process. Then schedule another IQ test and make sure you get lots of sleep prior to taking the test. Sufficient sleep is particularly important in tests involving short term memory. When you are tired, you will notice that it’s much harder to store and process new information. When I was writing mathematics textbooks, I sometimes pulled an “all-nighter”–going 24 hours without sleep. Later, when well-rested, I would check my work and find more than the usual number of errors that required correction.
So, take another test and you will probably receive a higher score. If not, don’t worry, your IQ is high enough to do most things you will need to do in life and your success in reaching your dreams will depend more on your intensity of purpose and work ethic than on your IQ.