L.S.
Has something changed in the family routine? Are you working more outside the home? Does he have a new sitter or daycare situation? SOOO many things are going on developmentally with children in the 2-3 year range. Growth spurts (seemingly non-stop eating), and huge emotional and developmental leaps. Onset of better verbal skills, gross motor skills, new social skills. A big time of change.
He NEEDS you and is stating it clearly. I truly believe that a child's needs for his parent/caregiver do not go away because the sun goes down or a calendar date passes. Meet your little guy where he is at. It IS exhausting to be up a night... especially when you have to get another little one going in the morning, but it is well worth it to meet the need when it occurs. Does he need some one-on-one time with you daily, outside of the regular hustle bustle?
Other advice about diet and bedtime CALM routines are helpful too. One thing I have found is that when these little ones are over-tired (missed naps, etc) it makes them MORE wakeful at night, not less.
Good luck Mama... relax and realize that this could just be a little developmental hiccup and that "this too shall pass"