Do you have one gallon in the fermentor? Depending upon when you pitched the yeast it may not be too late to top off with boiled, cooled (to fermentor temperature), and aerated water.
You do not need to apply so much heat to the boil kettle to create mini volcanoes to have a boil. Excess heat will just cause the extract to become darker in the finished wort. Boiling is by temperature. 212°F is boiling at seal level. Boil temperature is 1°F less for every 500 feet above sea level. My boil temperature at approximately 1485 feet is 209.5°F.
When you go to 5 gallon recipes we can talk about late extract addition to keep the wort a lighter color.
Now comes the patience part of brewing a good beer. It's easy though. The yeast are doing all the work now. They just need the right temperature and time to finish the job.
Welcome to the forum.
Here is a link to John Palmer's previous "How To Brew" edition on using a hydrometer. New edition will be a very good investment.