Struggling to empty my breasts

Help!

I've been pumping for 3 months now, not very successfully. I originally was using an Ameda Mya pump and just bought a spectra S2 plus.

I cannot seem to pump more than an ounce per breast in a 30 minute session.

I've tried all flange sizes from 17mm to 28mm. Finally found the right size that felt comfortable and aided in milk collection. Also consulted with an IBCLC about that.

With the spectra I cannot get a steady stream of milk for more than a minute at any setting but am most successful at 70/L4. I've been playing around with settings for a few weeks now and feel even more confused!

I have made sure my duckbill valves and backflow membranes were in top shape. I'm hydrated and make sure to spend time doing a breast massage before and during pumping as well as heat therapy. I have a calming corner where I pump with my music and lights.

I've tried single breast pumping, double pumping, power pumping, pumping after nursing, between nursing...

I need advice! The only way I can empty my breasts is with baby!