Decrease in milk supply at 6 months

Anyone else experience a drop in milk supply at 6 months? Had Been saving about 6-10 ounces more than what baby consumes and now I'm just skating by. Producing just enough for him.. I was so much more comfortable when I was having extra. No idea what has caused the sudden drop the last 2 weeks. Baby eats one meal of baby food a day but it's right after he nurses at 4- 4:30 and then he will nurse at bed time at 7. Nothing has changed. I am a working mom and my pumping times haven't changed but my supply has dropped. My baby will get angry was flail himself off the boob when I nurse him before bed. I think it's because 1) supply is always lighter at night and 2) my supply has dipped so now he struggling to get enough milk during the last feeding of the day. It's a little worrying. Why is my milk dropping:( feeding him baby food shouldn't affect him that much and he feed shortly after I nurse him so he's taking a full feeding before.