Breast Feeding Problem

[name_m]Hi[/name_m] Reader/Advice Giver,
Here is my situation: my little guy just started sleeping through the night. He is 3 months old exactly. He has reflux, so I didn’t try to sleep train him like I did my first, he just naturally started doing it on his own (hooray! More sleep for everyone!) Anyway, with my first, once he started sleeping through the night, I began to lose my milk. By the time he was 4 months old, we had to switch to formula. I would really like to make it at least 6 months this time, if possible. Now that little man has dropped the middle of the night/early morning feeding, he is only nursing 4 x a day. The last feeding of the night is where I notice the problem. I don’t have enough milk for him. Tonight I nursed him for an hour, then gave him an extra 2 oz. of pumped breast milk and he finally had enough to go down for the night. I’m pumping every night, before I go to bed, after I’ve feed him. Plus, I’m pumping after the first morning feeding, which is when I have the most milk. So, between the two pumping sessions, I usually have at least 2-4 oz of available breast milk in the fridge. I’m concerned this is just my body’s way of operating, and despite my best efforts, I’m on the way to losing my milk by [name_m]Kurt[/name_m]'s 4th month too. Is there anything I’m missing? (I’m looking for advice other than to get up on my own in the middle of the night and pump. I’m dedicated, but I don’t know that I’m that dedicated.) What am I doing wrong?
Thanks for the help!