Lindsay Lohan Morgue Duty -- I See Dead People

Lindsay Lohan won't be touching any dead bodies during her stint on morgue duty this morning ... but TMZ has learned she's already come face to face with a real not-live human corpse.

Sources tell us ... Lindsay is on sheet-washing duty ... and she covered her mouth in horror when she first laid eyes on the blood and fluid stained linens.

We're told ... during her shift, Lindsay saw a dead body in the morgue and seemed "shocked."

Lohan has just moved on to toilet duty.

Sources also tell us Lindsay appears to be in good spirits ... is talking to other people in her group ... and is maintaining a positive attitude.