The short answer is YES, you lost part or all of your NOL from 2015 and 2016.
Because you did not file the election to "waive the carryback", it is now past the Statute of Limitations to claim that NOL on your 2013 and 2014 returns.
If 2013 and 2014 would not have absorbed all of the NOL, then the non-absorbed amount would carry forward and can be used in 2018. The NOL from 2017 will also be able to be used because there was no income in 2015 and 2016 to absorb that loss.
But as the others have said, go to a tax professional that knows NOLs.
