help getting milk supply back up

Jackie
Ever since my daughter was 4 months I was breastfeeding her and giving her formula it was all working fine for me, over night I'll breastfeed her, early morning and afternoon and 3 bottles of formula for the rest of the day. It wasn't till one day my husband and I got in a HUGE argument and we will fight 24/7 and I would get so pissed off that I noticed my milk supply was going down, I would drink tea's that would help for my milk supply, pump and breastfeed at the same time but it got to the point where my daughter wasn't getting full, and I was only pumping 2oz, as time passed my daughter didn't want to latch on anymore because she would get frustrated that my milk wasn't coming fast and a lot like it used to (I would leak so much before) that I started giving her formula more, and now I only pump 1.5oz max or less. She's 6 months now but I was planning on breastfeeding only till 8months, I really want to accomplish that, any tips on how to get my supply back? I have heard that after 4 months whatever your supply is it'll remain like that till it dries up.