Beta question, esp twins

sovvv

My first beta at 14dp5dt was about 1200, then my second beta at 16dp5dt was about 3900.  My nurse and doctor won't comment yet, and my 1st ultrasound isn't for another week, but I'm wondering if it could be twins?  I know these numbers are really high for a singleton based on what I've found wandering around the web.  I wish betabase was up because I've heard that's really helpful. I guess I'm really just trying to pass the time until my sono by over-analyzing everything I possibly can