I have a unique situation. I graduated from a German University and was working full-time for three years post graduation. During this time I received the EU Blue Card and later the Niederlassungserlaubnis. However after three years that is 2017 I moved to my home country for personal reasons and have been living away from Germany for two years now. I read that the permanent resident card remains valid only for 6 months of living abroad. Is it possible to get the permanent resident status back by any chance. Any help will be appreciated. Also what if I get a job in Germany now.
You need to ask the corresponding Ausländerbehörde (before trying to enter Germany). A good idea would be to mention some personal issues that were the reason for you to leave Germany (because it could be a official reason to avoid the expiration of you residence permit, please see details here and here). Actually, you should have asked them before leaving Germany, then it could be easier to avoid expiration of your Niederlassungserlaubnis.
May I also ask you if you really got Niederlassungserlaubnis and not "Erlaubnis zum Daueraufenthalt-EU"? Cause the latter one expires after 2 years for former Blue Card holders.