great news!!! :clap
One last thing, from personal experience: are you under any additional stress? You said you aren't letting down, was this an overnight occurrence? That happened to me once when DD was about 7 or 8 months old. Mid terms were around the corner, I was stressed, and I couldn't let down and could only hand express about an ounce or less (my hands got tired) at a time. What it took for me, was just vegging in front of the TV for almost an entire TV episode (about 45 minutes) of pumping before I finally let down. After that, it started to take less and less time to pump again to get MY normal 3-4 ounces in a session (but I have a little peanut who doesn't eat as much as yours obviously). Good luck!
It started happening a few weeks ago. I don't feel stressed but we went from no kids to 3 kids in just over a year (adopted 2 boys July 2011, baby born January 2012). So...we've been through a lot. We are all still adjusting and overall doing well. My body always knows I'm stressed before my brain does :) I'm sure it is a combination of things.