Slacker boob, tips for increasing supply please

I have 1 boob that produces about 4-5oz per pumping and the other was at about 2oz but has been getting even worse, last session was less than a 1oz. I have tried power pumping and fear it damaged tissue somehow because ever since I've been getting knots in that breast. I have to sit there and squeeze it the entire time for it to empty out less than an ounce. Just ordered pumpin pal flanges because I feel that no matter what size I use too much areola gets pulled in. I start with nipple centered and then they start to point down and double in size. I feel if I don't dial in the problem I'm going to dry up on that side, soon. Ugh. Ready to give up. Help!