Regaining breast milk supply

So my little man is 4 months old and has only been breast feeding since he was 8 weeks old, for some reason he just wouldnt latch, anyway ive been trying to build my supply back up, it was like a river when my milk came in and now i could pump for ans hour and only get half an ounce, my milk didnt dry up and im trying to put him to breast as much as i can, ive just bought a haakaa pump so hoping that would help, just wanted some positive storys about women who came late to breast feeding or managed to build up their supply this late into it ans how you managed it

(Pic pf frankie so it doesnt get lost)