I full time expressed with DD due to poor attachment (small mouth, flat nipples) from 10 weeks until she was 6 months. It wasnt easy. I tried to get her back to B/Feeding at around 14 weeks but it just didnt work and was more stress than it was worth at the time.
It CAN be done but takes commitment and perseverance. Like someone else said, once you get in to a routine it gets easier. Initally I had oversupply but because a pump isnt as effective as baby getting the milk out, my supply dropped over time. I would express after every bottle she had, up to 120mls each feed (depending on supply at the time). Took fenugreek / blessed thistle, made lactation cookies and LOTS of water. I too found that a manual pump was more effective than an electric.
I figured that although I couldnt B/feed (and I felt VERY guilty about it and self-conscious when around other b/feeding mothers) I was still giving DD the very best and it doesnt matter how she gets it - via boob or bottle - its still breastmilk.
Good luck OP, remember even if you dont get to go back to b/feeding, its not the end of the world, just do whats best for BOTH you and bubs.