day 2 of refusing to nap

DS has decided to not nap for the 2nd day in a row.  He's very obviously exhausted, and is eating like crap because he's so tired and fussy.  I've even tried holding him and letting him sleep on me.  The most I can get is 15 mins.  He only napped about 2 hrs the whole day yest and slept like crap last night (11-1:30, 2-4:30, catnapped 5-8 in the bed w/me).  I started trying to put him down for the night at 8 (like usual).  I feel like he should be sleeping much, much more than this.  And I'm heading back to work on Monday and starting to get a little concerned.  His sleeping habits are getting worse, not better......

Think I may go for a car ride to see if I can get him to sleep for longer than 15 mins.