Need help..Going back to work soon!!!

I'm going back to work in a month and I haven't been able to freeze any milk.. I produced barely enough to feed my son through out the day.. I tired pumping while he sleeps but he only wakes up shortly after to nurse.. I need help so I can have milk stored for when I return to work. I've tried almost everything to increase my supply. I was able to nurse my first son 5 years ago with no problem and store milk. Please help my son is now 7 weeks.