Low milk supply

When I had my LO in Nov I was producing more than enough colostrum and started producing milk about 4-5 days later. I was getting about 4-10oz per pumping session. Fast forward a month later and now I'm barely getting 3oz per pump and that's both sides combined. My son will latch when he wants to but I still try to pump after each feeding. I know breast is best and want him on BM until at least 1yo. How can I increase my milk production? I'm drinking the Mothers Milk tea, raspberry leaf tea, eating tuna, yogurt, oatmeal (all foods I don't care to eat because they've always made me naseaous whenever I ate them for years). Ive increased my water intake drastically as well. PLEASE HELP!!!