Lost in the nether, how can I find my original portal? [duplicate]
If you are not too far from the portal and on an open zone then build something big that doesn't look natural and suicide. Then you will be back in your home. Then find the portal you built and go into it now look for the thing you built before and run there a loot your items back. Then go back to your portal and be back home! :)
If you're playing single player you can backup your files and suicide. When you respawn do a F3 and note your coordinates. Restore your backup and head for those coordinates.