I started up P90X again last night and had some crazy pain in my right elbow.  I've been slacking off for the most part but have worked out sporadically over the last few months.  Did some pushups last week without any problems.  This feels like tendonitis but I've never really had it before.  

Any recommendations on treating it?  Should I not workout until it's completely gone?  Should I try to work through it?  See a doc?   Not really sure where to go from here.

If it is tendonitis, you need to completely rest it for atleast a week or two. Ice 2-3x per day in the mean time and stretch periodically. See a sports medicine doc if it persists. I got tendonitis pretty bad in my knee (hamstring tendonitis) on a backpacking trip so I couldn't just call it a day and go home and ice. The nearest road was about 10 miles away and we had to cross a couple mountains. By the time we got to the road and found a house with a landline, I could barely bend my knee. It took me 2 months to get back to jogging and cropped back up in the fall. Don't try and push through the pain, else you may have cronic problems.

Is it nerve pain?  I ask only because I thought I had tendonitis in my right elbow, but realized that it was nerve pain.  This led me to learn about Orbital Tunnel Syndrome, and "nerve gliding" exercises that have almost eliminated my elbow pain.

I'm pretty sure it's tendonitis.  going to take it easy on it and see what happens.

doing chin-ups, then aggressive massage followed by warm heat helps tendon issues, take Ibu. At least it did with my 4 bouts with a variety of tendon issues.
 

just adding to the choir here.

Minor tendonitis can be easy managed with rest. Severe tendonitis can sideline you. dont let it get to that point.